CD274 and neoplasm: Mechanically, tumor cells are able to regulate immune cell activation, chemotaxis, and polarization through paracrine secretion of cytokines, chemokines, and growth factors, or through direct cell-cell interaction signals, such as tumor antigens presented by major histocompatibility complex class l (MHC-I), programmed death ligand 1 (PD-L1), and CD47.282 In turn, a remodeled immune ecosystem supports further malignant progression.