Developers of cancer immunotherapies are in a race to find combinations that can distinguish their products for specific indications. Biomarkers, which have played an essential role in the development of targeted therapies, have proven a much more complex challenge in the realm of immuno-oncology. Nevertheless, biomarkers may be the key to winning the competitive battles in immuno-oncology. We spoke to Rachel Laing, managing partner of Bionest Partners, about the role for biomarkers in immuno-oncology, why immuno-oncology companies have much at stake in the hunt for biomarkers that can better select patients for their therapies, and the role biomarkers will play in the move toward real-time oncology.