 This is a phase 11b open-label, multicenter, dose-selection study of CPI-444, an oral small molecule targeting the adenosine-A2A receptor on T-lymphocytes and other cells of the immune system. This trial will study the safety, tolerability, and anti-tumor activity of CPI-444 as a single agent and in combination with atezolizumab, an intravenous PD-L1 inhibitor. CPI-444 blocks adenosine from binding to the A2A receptor. Adenosine suppresses the anti-tumor activity of T cells and other immune cells. 