James Larkin, MD, PhD, of the Royal Marsden NHS Foundation Trust, London, UK discusses the use of the new immunotherapy checkpoint inhibitors, and the influence they have had on melanoma. He proceeds to state that even in the best case scenario, response rate to treatment with both ipilimumab and nivolumab (IPI+NIVO) is around 50-60%, and with NIVO or pembrolizumab (PEMBRO), the response rate is around 30-40%. Given these figures, it is clear that there are a substantial number of patients who are not responding to treatment. The immune system is complicated and understanding who will respond to treatment and why is therefore difficult according to Dr Larkin. With BRAF inhibitors and BRAF mutations, it is possible to understand from a theoretical point of view who will respond, however, there are many factors that may have an influence, such as the level of immunity and the location/role of the immune cells. He believes that in the future, there should be the possibility of looking at all the factors to derive a composite score, which would perhaps give a good idea of what treatment is required at each situation. He highlights that the tumor PD-1 expression could be one of those criteria, but subsequently mentions that he does not believe that it could be useful in isolation. Recorded at the American Society of Oncology (ASCO) 2016 Annual Meeting held in Chicago, IL.