PDCD1 and melanoma: Accordingly, in the randomized, phase III KEYNOTE-054 study, which investigated the anti-PD1 monoclonal antibody pembrolizumab versus placebo in resected high-risk stage III melanoma, the results showed a significant prolongation of recurrence-free survival (RFS) at 3 years (63.7% vs 44.1%, hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.47 to 0.68) [4].