CD8A and lung adenocarcinoma: Nevertheless, various immune inhibitory factors exist within the lung adenocarcinoma environment, such as immune suppressive factors in the tumor microenvironment and overexpression of PD-L1, which may lead to the inhibition and exhaustion of CD8+ T cell function, thereby weakening their anti-tumor effects (Liu et al. 2022; Zhang et al. 2021; Li et al. 2022a, b).