Furthermore, PD1Hi CD8+ T cells exhibited defective production of IFN-γ and TNF-α (median = 35.09, 7.44–67.41%; median = 13.47, 2.12–30.58%), which are typical Th1 cytokines essential for effective anti-tumor responses, in comparison with the PD1Int (median = 77.01, 61.25–82.34%; P = 0.0059; median = 70.67, 60.70–80.60%; P = 0.002) and PD1− CD8+ T cell (median = 71.74, 49.70–90.09%; P = 0.002; median = 58.74, 54.47–80.20%; P = 0.002). The gene discussed is CD8A; the disease is neoplasm.