CD274 and non-small cell lung carcinoma: <b>Methods</b>: We retrospectively reviewed patients with metastatic NSCLC and a PD-L1 TPS ≥ 50% who initiated first-line treatment with pembrolizumab monotherapy or pembrolizumab combined with platinum-based chemotherapy at the Istanbul Medipol University Department of Medical Oncology between July 2017 and December 2024.