CD8A and cancer: Regulatory T cells with strong immunosuppressive function have been shown to infiltrate heavily into various cancer tissues including LUAD.[36,37] Regulatory T cells undergo immunosuppression within TME through activation of STAT signaling molecules.[38,39] They can also competitively bind IL-2,[40] secrete TGF-β and IL-10[41] thereby inhibiting CD8 + T cell activation, proliferation, and the ability to kill tumors.