Abstract
Immunotherapy targeting "immune checkpoints" first made the headlines at the ASCO (American Society of Clinical Oncology) Annual Meeting in 2013, took centre stage at 2014 and consolidated its position as a potentially curative first-line therapy as reflected by the presentations at ASCO 2015. For the first time, previously refractory cancers are proving amenable to treatment, but still only a fraction, usually a minority, of patients respond. The hunt for factors predicting responses and for biomarkers to monitor treatment was a major theme of this year's meeting, as briefly discussed in this Editorial.