Study to Compare the Safety and Efficacy of CMB305 With Atezolizumab to Atezolizumab Alone in Participants With Sarcoma (IMDZ-C232/V943A-002)

Inclusion Criteria: * Locally advanced, relapsed, or metastatic sarcoma with measurable tumor burden following therapy, as defined by Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1); the total of all lesions must be ≤12 cm (for synovial sarcoma) or ≤15 cm (for myxoid/round cell liposarcoma \[MRCL\]) * Tumor histology consistent with synovial sarcoma or MRCL * Tumor specimen positive for NY-ESO-1 expression by immunohistochemistry (IHC) * Inadequate response, relapse, and/or unacceptable toxicity with ≥1 prior systemic, surgical, or radiation cancer therapies * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Exclusion Criteria: * Investigational therapy within 4 weeks prior to CMB305 dosing * Prior administration of other NY-ESO-1-targeting immunotherapeutics * Prior treatment with CD137 agonists or immune checkpoint blockade therapies, including anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death receptor 1 (PD-1), and anti-programmed cell death ligand (PD-L1) therapeutic antibodies, or any other antibody or drug targeting T-cell costimulation * Treatment with systemic immunostimulatory agents (including but not limited to interleukin-2) within 4 weeks or five half-lives of the drug, whichever is shorter, prior to first dose * Significant immunosuppression * Other cancer therapies, including chemotherapy, radiation, biologics or kinase inhibitors within 3 weeks prior to the first scheduled dosin…