This is a Phase 1b/2 study, multicenter, open-label, randomized study in patients with nonsquamous non-small cell lung cancer without prior treatment for metastatic disease. Part 1 is designed to identify the recommended Phase 2 dose (RP2D) of vudalimab, an anti-PD-1/CTLA-4 bispecific antibody, in combination with standard of care (SOC) chemotherapy. Part 2 will evaluate the efficacy and safety vudalimab, at the RP2D, plus SOC relative to pembrolizumab (anti-PD-1) plus SOC chemotherapy.