CD8A and neoplasm: Regulatory CD4+ T lymphocytes (Tregs) and tumor-associated macrophages (TAMs) are prototypical immunosuppressive cell types in the TME, suppressing the function and proliferation of effector CD4+ and CD8+ T cells as well as NK cells by secreting or enhancing the secretion of immunosuppressive molecules such as interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) [12–14].