Background: RCTs have tested the role of adding immunotherapy to standard therapy in patients with advanced non-squamous non-small cell lung cancer (NSCLC) in the first-line setting. We conducted a systematic review and meta-analysis of RCTs to assess the efficacy and toxicity of adding immunotherapy in this patient population. Methods: We systematically conducted a comprehensive literature search using PUBMED, EMBASE and SCOPUS databases through October 1, 2018. RCTs of first-line standard therapy +/- immunotherapy in patients with advanced non-squamous NSCLC were incorporated in the analysis. A generic inverse variance method was used to calculate the estimated pooled Hazard ratio (HR) for overall survival (OS) and progression-free survival (PFS). The mantel-haenszel method was used to calculate the estimated pooled risk ratio (RR) with 95% confidence interval (CI) for pooled overall response rate (ORR), all-grade adverse events (AEs), and high-grade AEs (≥grade 3). Heterogeneity was assessed with Cochrane Q-statistic. Random effects were used due to significant heterogeneity among studies. Results: Three phase 2 & 3 RCTs (Keynote – 021,189 and IMpower – 150) including 1431 patients with advanced non-squamous NSCLC patients were included in the analysis. Keynote 021 & 189 trials did not allow patients with EGFR or ALK mutations, while IMpower 150 trial allowed EGFR or ALK mutations. The study arm used standard regimens in combination with pembrolizumab or atezolizumab while control arm used only standard regimens. The pooled HR for PFS was 0.57 (95% CI: 0.5-0.65; P=0.00001), the pooled HR for OS was 0.61 (95% CI: 0.43-0.87; P=0.006), and the pooled RR for ORR was 1.83 (95 CI: 1.13-2.95; P=0.01). The pooled RRs for all-grade AEs and high-grade AEs were 1 (95% CI: 0.99-1.02; P=0.48) and 1.11 (95% CI: 0.97-1.28; P=0.14), respectively. Conclusions: Pooled data showed significant improvement in PFS, OS & ORR with chemo-immunotherapy compared to the standard treatment regimen for the first-line treatment of advanced non-squamous NSCLC. There was no increase in the risk of all-grade and high-grade AEs.