Therapies with immune checkpoint inhibitors (ICI) targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed cell death ligand 1 (PD-L1) are associated with increased T cell activation and effective anti-tumor immune responses [63]. This evidence concerns the gene PDCD1 and neoplasm.