In patients with NSCLC, pembrolizumab, an anti–PD-1 therapy, in the first-line setting showed superior efficacy compared with PDC in those patients who had PD-L1 expression in > = 50% of viable tumor cells without epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK) aberrations [17, 18]. This evidence concerns the gene ALK and non-small cell lung carcinoma.