PD-L1 on the NSCLC cell membrane was found to paralyze CD8 + T cells, and in coculture of NSCLC cells and CD8 + T cells, removing circ-CPA4 reactivated CD8 + T cells, suggesting that circ-CPA4 enhanced PD-L1 expression by sponging let-7 to regulate cell growth, mobility, stemness and drug resistance and to inactivate CD8 + T cells in the TME in NSCLC. This evidence concerns the gene CD8A and non-small cell lung carcinoma.