Immuno-Oncology Biomarker Trends to Watch Heading Into 2027

Immuno-Oncology Biomarker Trends to Watch Heading Into 2027

Every autumn, the immuno-oncology field releases a wave of new data in a few short weeks. This year, SITC 2026 in Phoenix (4–8 November) opens that season, and the results presented over the coming months will shape biomarker strategy, trial design and partnering decisions well into 2027.

The challenge for translational, biomarker and business development teams is not finding new data. It is deciding which signals matter for their programmes, and which are noise.

This guide covers the five immuno-oncology biomarker trends we think will matter most heading into 2027, what to look for in each, and how to turn a busy conference season into decisions.

Key takeaways

• Patient selection, not new mechanisms alone, is now the main bottleneck for IO programmes.
• Cell therapy, T cell engagers and cancer vaccines are moving deeper into solid tumours, and each needs its own biomarker strategy.
• PD-L1 and TMB remain the clinical baseline, but they are no longer enough on their own.
• Spatial biology, ctDNA and AI are maturing fast; the open question is which signals hold up in prospective trials.

1. Cell therapy moves into solid tumours

CAR-T transformed blood cancers. Solid tumours are a harder problem: antigen heterogeneity, a hostile tumour microenvironment and limited T cell persistence all work against durable responses. New approaches, including armoured and logic-gated CAR-T, TCR-T, NK cell therapies and in vivo CAR-T generated inside the patient, are all aiming at the same gap.

What to look for: evidence on antigen expression thresholds, early markers of T cell expansion and persistence, and tumour microenvironment features that predict who responds.

What it means for biomarker teams: response prediction needs to start before dosing. Our analysis of CAR-T cell therapy biomarkers covers the markers with the strongest evidence so far.

2. T cell engagers and bispecifics go beyond blood cancers

Bispecific T cell engagers have proven themselves in haematological cancers, and the field is now pushing them into solid tumours. That raises two biomarker questions at once: is the target expressed widely enough to drive response, and is it absent enough from healthy tissue to keep toxicity manageable?

What to look for: target expression data across tumour and normal tissue, cytokine release and on-target toxicity patterns, and early pharmacodynamic markers of T cell activation.

What it means for biomarker teams: target selection and patient selection are becoming the same conversation. Expect more programmes to build a companion diagnostic strategy from the first in-human study.

3. Neoantigen vaccines and the T cell response problem

Personalised cancer vaccines are back at the centre of the field, often in combination with checkpoint inhibitors. Their success depends on two things that are hard to measure: choosing the right neoantigens, and proving that the vaccine produced a meaningful T cell response.

What to look for: how programmes select and rank neoantigens, which immune monitoring assays they use, and whether vaccine-induced responses track with clinical outcome.

What it means for biomarker teams: immune monitoring is becoming a core trial capability, not an exploratory add-on. Assay standardisation will decide which data sets are comparable across programmes.

4. Predictive biomarkers beyond PD-L1 and TMB

PD-L1 expression and tumour mutational burden remain the clinical baseline for checkpoint therapy. But both leave too many patients misclassified, and neither was designed for the combinations now entering trials.

What to look for: composite signatures that combine tumour, immune and microenvironment features; immune gene expression profiles; and markers developed specifically for combination regimens.

What it means for biomarker teams: single-analyte biomarkers will increasingly sit inside multi-marker models. That changes validation requirements and the regulatory path for any companion diagnostic built on them.

5. Spatial biology, ctDNA and AI read the tumour microenvironment

Spatial transcriptomics and proteomics, multiplex imaging, ctDNA and MRD monitoring, and AI-driven pathology are giving teams a far richer view of the tumour and how it changes on treatment. The multiplex platform landscape alone has changed significantly in the last two years.

What to look for: spatial features that predict response rather than just describe it, ctDNA dynamics as an early read-out of benefit, and AI models validated on independent cohorts.

What it means for biomarker teams: the technology is no longer the constraint; validation is. Our guide on validating an IO biomarker in a clinical trial sets out the standards a signal needs to meet before it can guide treatment.

What to look for in SITC 2026 data

If your team is following the data coming out of SITC 2026, read it through the five lenses above. For each result, ask three questions: does it identify which patients benefit, can the biomarker be measured reliably outside a single lab, and is there a realistic path to a validated assay? Results that answer all three are the ones likely to change programmes in 2027.

Getting value from conference season

For business development and partnering teams, the autumn congresses are as much about meetings as data. A few habits make the difference:

• Build a target list early. Decide which companies and investigators you need to meet, and request meetings before schedules fill up.
• Split the team by theme. Assign owners for cell therapy, engagers, vaccines and biomarker technology rather than trying to cover everything together.
• Prioritise posters. Some of the most useful early data, and the easiest conversations with authors, happen away from the main stage.
• Follow up within 48 hours. Specific, contextual follow-up is the strongest predictor of whether a conversation becomes a partnership.

Where these conversations continue in 2027

Large congresses are where new data first appears. The follow-up conversations about turning that data into biomarker strategy, trial design and partnerships happen in smaller, more focused rooms.

That is what ImmunoMark Summit San Diego is built for. On 10–11 February 2027, 300+ senior pharma, biotech and diagnostics leaders meet in two parallel streams that map directly onto these trends: Immuno-Oncology (cell therapy, engagers, vaccines, resistance) and Biomarkers & CDx (liquid biopsy, spatial and multi-omics, AI, CDx co-development), with pre-arranged 1:1 meetings and a Day 1 Drinks Reception.

The series continues in London on 3–4 March 2027 and Boston in June 2027. For the wider calendar, see our list of the best immuno-oncology conferences to attend.

Register for ImmunoMark San Diego 2027

If your company wants to meet this audience directly, see the San Diego 2027 sponsorship packages.

FAQs

What are the biggest immuno-oncology trends heading into 2027?

Cell therapy for solid tumours, T cell engagers beyond blood cancers, neoantigen vaccines, predictive biomarkers beyond PD-L1 and TMB, and spatial biology, ctDNA and AI for reading the tumour microenvironment.

When and where is SITC 2026?

SITC 2026 takes place from 4 to 8 November 2026 at the Phoenix Convention Center in Phoenix, Arizona.

Why are biomarkers the bottleneck in immuno-oncology?

Most IO therapies work very well for a minority of patients. Without reliable biomarkers to identify those patients, trials are harder to run, approvals are harder to win and therapies reach fewer of the people they could help.

Where can IO and biomarker teams discuss these trends in 2027?

ImmunoMark Summit San Diego on 10–11 February 2027 brings together senior pharma, biotech and diagnostics leaders in two parallel streams, Immuno-Oncology and Biomarkers & CDx, with pre-arranged 1:1 meetings.