PDCD1 and melanoma: Clinical trials on the use of other monoclonal antibody-based drugs that target CTLA-4 (tremelimumab) (136–139), PD-1 (pembrolizumab, nivolumab, and pidilizumab) (140–142), and PD-L1 (BMS-986559, MPDL3280A, and MEDI4736) (143–145) as treatment strategies for melanoma, renal cell carcinoma, and non-small cell lung cancer have either been completed or ongoing.