CD274 and neoplasm: Immune evasion is affected by PD-L1 upregulation, secretion of immunosuppressive cytokines (IL-6, IL-10, TGFβ, and MCSF) and suppressive immune cells recruitment such as M2 macrophages, regulatory T (Treg) cells and myeloid-derived suppressor cells (MDSCs), which eliminate immune-mediated tumor cell killing by suppressing Natural Killer (NK) cells and CD8+T cells (34).