IFNG and cancer: The secretion of IFN-γ by T lymphocytes increased the expression of PD-L1 on cancer cells, thereby enhancing the efficacy of the immune checkpoint inhibitor atezolizumab, as demonstrated in the contacting co-culture assay, thus suggesting that a high PD-L1 level can be considered as a “driver” for T cell-mediated anti-tumor activity of immune checkpoint inhibitors.