ALK and non-small cell lung carcinoma: They found low PD-L1 expression and low CD8+ T cell infiltration [4,5,6] in ALK+ NSCLC, potentially through the activation of PI3K, MAPK, and Hippo pathways [7,8], However, some inconsistent or even opposite results regarding PD-L1 expression and CD8+ T cell infiltration were also revealed by other studies [7,9,10].