CD274 and non-small cell lung carcinoma: Our systematic review/meta-analysis included a multicenter study from Europe, which included patients with NSCLC with PD-L1 expression ≥ 50%, compared the outcomes of salvage chemotherapy versus pembrolizumab (with or without local ablation therapy) in patients with advanced NSCLC exhibiting high expression of PD-L1 who had progressed after first-line immunotherapy.