Shima et al. [14] found that when lung cancer cell lines were cocultured with M2-polarized TAMs, the expression level of human lung cancer cell lines A549 and H1975 was increased remarkably, and inhibition of transforming growth factor-β (TGF-β) decreased PD-L1 expression to the baseline level. This evidence concerns the gene TGFB1 and lung carcinoma.