CD8A and neoplasm: In most tumors, the anti-cancer immune response carried out by the cytotoxic lymphocyte subsets, CD8+ T cells and natural killers (NKs) is defective, and as a counterpart, immunosuppressive cells such as MDSCs, neutrophils, immune regulatory T (Treg) and M2-like macrophages are recruited to tumor site to aid tumor growth [81].