PDCD1 and non-small cell lung carcinoma: However, several researchers insist that using negative PD-L1 expression as the exclusion criteria for anti-PD-1/PD-L1 antibody therapy has limitations because some patients who are PD-L1-negative also show a response to anti-PD-l/PD-L1 agents in clinical trials for non-small cell lung cancers [46].