IDO1 and non-small cell lung carcinoma: We therefore asked if MEK pathway may influence activation of other immune checkpoint molecules and in particular of Ido-1; we analyzed the protein expression levels of MAPK, MEK, PD-L1 and Ido-1 in a panel of NSCLC established cell lines harboring WT or mutant KRAS gene (A549 and H460, KRAS mutated (G12C/G12S/Q61H) and H1299, KRAS WT) after IFNγ stimulation and after treatment with the MEK-inhibitor, selumetinib (Fig. 2).