Altogether, we hypothesize that IFN-γ might be secreted not merely to mount a potent immunity against tumor, and meanwhile induces an immune resistance, such as PD-L1/PD-1 inhibitory signaling, to protect from exorbitant immune reaction, however, they are often wittingly coopted by cancer cells to evade host immunity [15, 38]. This evidence concerns the gene PDCD1 and neoplasm.