ALK and lung cancer: Among the 30% of patients whose tumors express PD-L1 with a TPS ≥ 50%, other clinical exclusion criteria limit the extended use of pembrolizumab in the first-line setting, for example exclusion of patients considered unfit or with poor PS (representing almost 34% of NSCLC patients in contemporary cohorts [28]), patients with EGFR-mutant and ALK-rearranged tumors (approximately 17% of adenocarcinoma lung cancers in Caucasian populations [29]), and the absence of steroids or autoimmune disorders (13.5% of lung cancer patients [30]).