Atezolizumab and Cabozantinib for the Treatment of Adolescents and Young Adults With Recurrent or Metastatic Osteosarcoma, TACOS Study

This study (called TACOS) tests a combination of atezolizumab (immunotherapy) and cabozantinib (a targeted drug) in adolescents and young adults with osteosarcoma (bone cancer) that has come back or spread after prior treatment. **You may be eligible if...** - You are 12 years of age or older - You have been diagnosed with osteosarcoma confirmed by biopsy - Your cancer has spread (metastasized) or cannot be surgically removed - Your cancer has relapsed or stopped responding to standard treatments (including drugs like cisplatin, doxorubicin, methotrexate, or ifosfamide) - You have measurable disease on imaging scans **You may NOT be eligible if...** - You have never received prior standard chemotherapy for osteosarcoma - Your cancer is a different type of bone tumor - You have active autoimmune disease or are on immunosuppressive therapy - You have severe heart, liver, or kidney problems - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.