Numerous research reports have demonstrated that active IFN-γ signaling is a characteristic that is shared by most tumors in the IFN-γ-tumor relationship through targeting cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) antibodies when subjected to immune checkpoint blockade (ICB) (15, 16). Here, PDCD1 is linked to neoplasm.