PDCD1 and neoplasm: Monoclonal antibodies against immune checkpoint blockade molecules—such as CTLA-4 (cytotoxic T lymphocyte antigen 4), PD-1 (programmed cell death 1), and PD-L1 (programmed cell death ligand 1)—target the tumor microenvironment (TME) with an obvious objective response rate for KIRC [7].