Introduction: A series of randomized controlled trials have investigated different first-line immunotherapy combinations, but the optimal combination strategy is yet to be established. Methods: We performed a systematic review and Bayesian network meta-analysis by retrieving relevant literature from PubMed, EMBASE, Cochrane Library, ClinicalTrials.gov, and major international conferences. We included published and gray sources of randomized clinical trials comparing immunotherapy combinations with other treatments as first-line treatments for patients with advanced NSCLC. This study was registered in the Prospective Register of Systematic Reviews (CRD42020210501) to ensure transparency. Results: We analyzed a total of 16 studies involving 8278 patients and including 10 immunotherapy combinations. For patients without programmed death-ligand 1 (PD-L1) selection, pembrolizumab plus chemotherapy was found to be comparable with sintilimab plus chemotherapy in providing the best overall survival (OS) benefit (hazard ratio = 0.96, 95% confidence interval [CI]: 0.72–1.29). Furthermore, atezolizumab plus bevacizumab plus chemotherapy seemed to provide the best progression-free survival (hazard ratio = 0.45, 95% CI: 0.36–0.55) and the best objective response rate (OR = 0.23, 95% CI: 0.12–0.42). Subgroup analysis by PD-L1 suggested that nivolumab plus ipilimumab plus chemotherapy was associated with the best OS in patients with PD-L1 less than 1% and that pembrolizumab plus chemotherapy was associated with the best OS in patients with PD-L1 greater than or equal to 1%. Pembrolizumab and sintilimab were associated with relatively fewer grade greater than or equal to 3 adverse events when compared with other immunotherapies combined with chemotherapy. Conclusions: Our results suggest that antiprogrammed death-1 combinations are associated with potentially higher survival outcomes than anti–PD-L1 combinations with comparable safety profiles. Moreover, pem-chemo and nivo-ipi-chemo seem to be superior first-line immunotherapy combinations for patients with advanced NSCLC with positive and negative PD-L1 expression, respectively. Although atezo-beva-chemo treatment provided the best progression-free survival and objective response rate, the addition of chemotherapy to immunotherapy would increase the toxicity, especially when antiangiogenesis drugs are simultaneously added.