PDCD1 and neoplasm: However, there are still many patients who do not have genetic mutations [6], who might benefit from immune checkpoint inhibitors (ICIs), particularly antibodies targeting the programmed cell death-1 (PD1)–programmed cell death ligand-1 (PD-L1) axis, which can restore the antitumor immune response of the body by blocking the immune suppression signals between the tumor and T cells [7].