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 dosing

   - History of autoimmune disease, including but not limited to myasthenia gravis,
   myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis,
   inflammatory bowel disease, vascular thrombosis associated with antiphospholipid
   syndrome, Wegener's granulomatosis, Sjögren's syndrome, Guillain-Barré syndrome,
   multiple sclerosis, vasculitis, or glomerulonephritis

   - History of idiopathic pulmonary fibrosis (including pneumonitis), drug-induced
   pneumonitis, organizing pneumonia (i.e., bronchiolitis obliterans, cryptogenic
   organizing pneumonia), risk of pulmonary toxicity, or evidence of active pneumonitis
   on screening chest computed tomography (CT) scan. History of radiation pneumonitis in
   the radiation field (fibrosis) is permitted

   - History of other cancer within 3 years

   - Evidence of active tuberculosis or recent (<1 week prior to first scheduled dosing)
   clinically significant infection requiring systemic therapy

   - Evidence of active hepatitis B (HepB), hepatitis C (HepC), or Human Immunodeficiency
   Virus (HIV) infection

   - Known active or untreated central nervous system (CNS) metastases

   - Pregnant, planning to become pregnant within 6 months of treatment, or nursing

   - Known allergy(ies) to any component of CMB305, atezolizumab, or severe allergic
   reactions to monoclonal antibodies, fusion proteins, or Chinese hamster ovary (CHO)
   cell products