IFNG and neoplasm: It is well known that the T cell receptor (TCR) on the tumor-reactive T cell surface recognizes tumor neoantigens and subsequently releases IFN-γ, which binds to the IFN-γ receptor (IFN-γR1/R2) on the tumor cell surface, activates downstream JAK-STAT signaling pathways and further initiates PD-L1 transcription in tumor cells [171, 173, 174].