PD-1 is highly expressed on Treg cells and PD-L1 is widely expressed in several stroma non-hematopoietic cells and in various tumors; Lastwika and collaborators have shown that the activation of the mTOR pathway regulates the PD-L1 expression in vitro and in vivo in lung carcinoma [77,78]. Here, CD274 is linked to lung carcinoma.