CD274 and neoplasm: Programmed death-ligand 1 (PD-L1, also known as CD274 or B7-H1), as the major ligand of PD-1, is usually expressed on antigen-presenting cells as well as on tumor cells, which can bind to PD-1 to induce T-cell apoptosis and exhaustion, thereby suppressing anticancer immunity 4, 5.