PDCD1 and melanoma: Anti-CTLA-4, PD-1 and PD-L1 Abs achieved European Medicines Agency (EMA) and United States (US) FDA approval for the treatment of a broad spectrum of neoplastic diseases (melanoma, non-small cell lung cancer, head and neck cancer, lymphomas, microsatellite instability-high (MSI-H) solid tumors, urothelial carcinoma, renal cell carcinoma, gastric cancer, hepatocellular carcinoma and Merkel cell carcinoma), in early and advanced settings, generating durable clinical responses in tumors of different origins [21].