Tiragolumab and Atezolizumab in Patients With Non-squamous Non-small Cell Lung Cancer (NSCLC) and Untreated Brain Metastases

Inclusion Criteria: * Patients must have histologically or cytologically confirmed non-squamous NSCLC. * In patients treated with the combination of tiragolumab and atezolizumab, patients must have PDL1 TPS \>50%, as determined by an FDA-approved test. * Patients must have asymptomatic brain metastases with at least one untreated evaluable (per RANO-BM) brain metastasis of 5 mm or more. A growing lesion previously treated with whole brain radiotherapy is acceptable given the lower incidence of radiation necrosis. Lesions previously treated with SRS may not be used as target lesions. o Patients are not required to have measurable disease outside the CNS per RECIST 1.1. * Prior chemotherapy, immunotherapy or radiation given with curative intent in early stage or locoregionally advanced NSCLC is permitted, if completed more than 12 months prior to initiation of study treatment. * Prior radiation with palliative intent in the metastatic setting to non-CNS lesions is permitted (no wash-out period). * Age ≥18 years. * ECOG performance status ≤ 1. * Life expectancy ≥12 weeks. * Patients must have normal organ and marrow function as defined below: * Absolute neutrophil count ≥1,500/mcL * Platelets ≥100,000/mcL * Total bilirubin ≤ institutional upper limit of normal (ULN) * AST(SGOT)/ALT(SGPT) ≤2.5 × institutional ULN * Creatinine Clearance (CrCl) ≥45 mL/min/1.73 m2 * No known history of HIV, with the following exception: patients who are HIV positive are eligible provi…