CTLA4 and non-small cell lung carcinoma: A systemic search was conducted in four databases (PubMed, Cochrane library, Embase, and Web of Science) from their establishment until January 17, 2024, for randomized controlled trials that investigated the use of the first-line PD-1/PD-L1 inhibitor plus CTLA-4 inhibitor in patients with advanced NSCLC.