CD274 and neoplasm: Tumor microenvironments usually contain increased regulatory immunosuppressive T cells, and tumor cells express key negative regulators, such as programmed death ligand-1 (PD-L1) and B7-H3, which inhibit the immune regulatory response induced by T cells, down-regulate or prevent the body’s anti-immune effect, and promote the disabling of immune function to help tumor escape (11, 12).