This is a multicenter, randomized, open-label, controlled Phase 3 trial of cabozantinib in combination with atezolizumab versus sorafenib in adults with advanced HCC who have not received previous systemic anticancer therapy in the advanced HCC setting. The primary objective of this study is to evaluate the effect of cabozantinib in combination with atezolizumab on the duration of progression-free survival (PFS) and duration of overall survival (OS) versus sorafenib. The secondary objective is to evaluate the activity of single-agent cabozantinib compared with sorafenib in this patient population.