Overview: This Phase 1 trial, sponsored by Baylor College of Medicine and led by Principal Investigators Meenakshi Hegde, MD, Shoba Navai, MD, and Nabil Ahmed, MD, investigates HER2-targeted CAR T-cell therapy combined with a checkpoint inhibitor in patients with advanced sarcoma including synovial sarcoma. A patient’s own T-cells are genetically modified to recognize HER2-expressing tumor cells. After lymphodepleting chemotherapy with cyclophosphamide and fludarabine, the modified T-cells are infused back into the patient. Starting one week later, patients receive either pembrolizumab (every three weeks) or nivolumab (every two weeks) to further activate the immune response against the cancer. Patients who tolerate the treatment well may receive additional T-cell infusions at 6 to 12 week intervals.