Immunity checkpoint inhibitors (ICIs), including programmed cell death protein 1 (PD1) and programmed cell death protein 1 ligand 1 (PD-L1) inhibitors, block the PD1/PD-L1 signaling pathway, relieve the immune escape of tumor cells, and kill tumor cells by activating cytotoxic T cells (14–16). Here, PDCD1 is linked to neoplasm.