To address this knowledge gap, we conducted a multicenter retrospective study evaluating the real-world outcomes of first-line pembrolizumab monotherapy in patients with metastatic, non-oncogene-addicted NSCLC and PD-L1 TPS ≥ 50% treated at the two largest lung cancer centers in central and southern Serbia. This evidence concerns the gene CD274 and non-small cell lung carcinoma.