CD8A and neoplasm: TME contains a considerable number of immune cells, such as effector CD8 T cells with antitumor effects, natural killer (NK) cells, dendritic cells (DCs), and regulatory T cells (Tregs) with immunosuppressive functions, as well as myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and cancer-associated fibroblasts cells (CAFs).