All-Trans Retinoic Acid (ATRA) and Atezolizumab for the Treatment of Recurrent or Metastatic Non-Small Cell Lung Cancer

PRIMARY OBJECTIVE: I. To determine the safety and tolerability of the combination of tretinoin (ATRA) and atezolizumab in patients with advanced non-small cell lung cancer (NSCLC) based upon the Common Terminology Criteria for Adverse Events (CTCAE) version 5 criteria. SECONDARY OBJECTIVE: I. To determine the efficacy of the combination of ATRA and atezolizumab in patients with advanced NSCLC, including progression-free survival (PFS), objective response (ORR), disease control rate (DCR), and overall survival (OS) based on modified Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. EXPLORATORY OBJECTIVE: I. To study the effect of ATRA on the levels of myeloid-derived suppressor cells (MDSCs) in peripheral blood of study patients. OUTLINE: Patients receive tretinoin orally (PO) on days 1-3 of cycles 1-3. Patients also receive atezolizumab intravenously (IV) on day 1. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 12 weeks.