Programmed death ligand 1 (PD-L1), also known as B7-H1 or CD274, is expressed on the activated T cells, B cells, macrophages, tumor cells, interstitial cells, and vascular endothelial cells (ECs), PD-L1 regulates inflammation in the heart, liver, placenta, cornea, retina, and etc. Here, CD274 is linked to neoplasm.