In addition to regulation of PD-1 expression on tumor-infiltrating T cells, resveratrol can function as a direct inhibitor of α-glucosidase/α-mannosidase that modulates N-linked glycan decoration of PD-L1, thereby promoting the ER retention of a mannose-rich, abnormally glycosylated form of PD-L1. Here, CD274 is linked to neoplasm.