The presence of immune cells with an activation profile reminiscent of anti-microbial or anti-viral defense responses such as CD8 + T cells, T helper 1 (TH1)-polarized CD4 + T cells, memory T cells, NK cells, γδ T cells, B cells, and activated myeloid cells in the TME is associated with a favorable outcome, while immunosuppressive myeloid cells and regulatory T cells (Treg) that are able to limit the anti-tumor properties of the former cells predict poor prognosis in most cancers [8, 116]. The gene discussed is CD8A; the disease is neoplasm.