CD8A and neoplasm: The PCa tumor microenvironment contains immune effector cells such as CD8+ cytotoxic T lymphocytes, natural killer (NK) cells, neutrophils, B cells, and proinflammatory M1 macrophages (16), but immunosuppressive populations like myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) predominate (17, 18).