In this study, researchers assigned 304 recruited patients who had been diagnosed with stage IV NSCLC with a PD-L1 expression of >50% and no sensitizing epithelial growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) mutations to either receive pembrolizumab (anti-PD-1 ICI) or platinum-based chemotherapy. This evidence concerns the gene ALK and non-small cell lung carcinoma.