CD274 and non-small cell lung carcinoma: In patients with metastatic NSCLC and no prior systemic therapy, pembrolizumab was approved by Food and Drug Administration (FDA) as a first line treatment for patients with PD-L1expression ≥50% based on the results of the KEYNOTE-024 (NCT02142738) study, and as a second line treatment for patients with NSCLC expressing PD-L1 in≥1% of neoplastic cells 11.