CD274 and neoplasm: Immune checkpoint inhibitors (nivolumab or pembrolizumab, PD-1 antibodies) enhance the anti-tumor immune response by blocking the signaling via suppressive immune checkpoint molecules PD-1, PD-L1 and CTLA-4 that are often expressed in the TME by tumor cells and immune cells, such as tumor associated macrophages (TAMs), as a mechanism of immune evasion.