ALK and non-small cell lung carcinoma: While ALK TKIs directly inhibited tumor viability and enhanced antitumor immunity via downregulation of PD-L1, anti-PD-1 antibody was effective in both crizotinib sensitive and resistant cell lines, suggesting the need for further study in anti-PD-1 blockade for treatment of ALK-rearranged NSCLC [28].