More attractively, adaptive antitumor immunity featuring T effector lymphocytes plays an even more important role in the immune response against tumors in cancer immunotherapy, which typically includes cytotoxic T cells (CD8+ T cells), T helper cells (CD4+ T cells: CD3+CD4+) and regulatory T cells (Tregs: CD4+CD25+Foxp3+) [46]. The gene discussed is CD8A; the disease is cancer.