Four classes of ICIs are approved by the FDA for the treatment of melanoma: ipilimumab (an antagonist of the cytotoxic-T lymphocytes antigen 4, CTLA-4) [40]; nivolumab and pembrolizumab, antagonists of programmed cell death protein 1 (PD-1) [41]; atezolizumab, an antagonist of programmed cell death ligand 1 (PD-L1) [42]; and relatlimab-rmbw, (a combination of the LAG-3-blocking antibody relatlimab and the programmed death receptor 1-blocking antibody nivolumab) [42]. This evidence concerns the gene PDCD1 and melanoma.