T cells are known to be the key factor in inducing the immune response during LC.<h4>Objective</h4>In this study, we aimed to screen and analyze RNAs associated with CD8(+) T cells and activated memory CD4(+) T cells in lung adenocarcinomas, a subtype of non-small-cell lung cancer (NSCLC-LUAD).<h4>Methods</h4>Gene expression RNA-seq data and clinical data of NSCLC-LUAD were downloaded from the XENA database. The gene discussed is CD8A; the disease is lung adenocarcinoma.