Immune checkpoint inhibitors (ICI), such as anti-programmed cell death 1 (anti-PD1), anti-programmed cell death-ligand 1 (anti-PD-L1), and anti-cytotoxic T-Lymphocyte associated protein 4 (anti-CTLA-4) agents, act by disrupting inhibitory mechanisms of T-cell activation facilitating T-cell mediated cytotoxicity to cancer cells [1]. This evidence concerns the gene PDCD1 and cancer.