Encouragingly, the combination of nivolumab (anti-PD-1 antibody) and ipilimumab (anti-CTLA-4 antibody) has been documented to improve the overall 5-year-survival of melanoma patients to 52% with a response rate of 58% (13), which underscores the importance of the interactions between melanoma cells and immune cells in the TME. The gene discussed is PDCD1; the disease is melanoma.