Adult patients with a histologically or cytologically documented metastatic NSCLC, with tumors that lack activating EGFR mutations and ALK fusions, are eligible for enrollment. Patients will be randomized in a 1:1:1 ratio to receive treatment with durvalumab + tremelimumab combination therapy + SoC chemotherapy, durvalumab monotherapy + SoC chemotherapy, or SoC chemotherapy alone. Tumor evaluation scans will be performed until objective disease progression as efficacy assessment. All patients will be followed for survival until the end of the study. An independent data monitoring committee (IDMC) composed of independent experts will be convened to confirm the safety and tolerability of the proposed dose and schedule.