Therefore, PD-L1 expression by cancer cells regulates several pro-carcinogenic mechanisms that can contribute to resistance: First, PD-L1 as an inhibitor of T cell effector activities; second, PD-L1 as an anti-apoptotic shield; and third, PD-L1 as a recruiter of MDSCs into the tumor microenvironment. This evidence concerns the gene CD274 and neoplasm.