PDCD1 and cancer: 2023). ICIs amplify T-cell-mediated immune response against cancer cells by blocking intrinsic down-regulators, which include cytotoxic T-lymphocyte antigen 4 (CTLA-4)and programmed cell death 1 (PD-1) or its ligand of programmed cell death ligand 1 (PD-L1) (Moslehi et al. 2021; Jo et al. 2024).