Children (less than 10 years of age) are eligible if they have been diagnosed with either a medulloblastoma tumor or CNS embryonal tumors of the brain or spinal cord. The standard approach to the treatment of these brain tumors in young children may include surgery, radiation therapy to the brain and spinal cord and chemotherapy. Radiation therapy is the use of high energy x-rays to kill cancer cells. Chemotherapy means treatment with cancer killing drugs. This research study will compare two different treatment regimens to see which is better for treating children with this type of brain cancer.

This study involves taking a study drug called INBRX-109. The overall goal of the study is to find out how safe and effective the study drug is in treating people that have been diagnosed with advanced or metastatic Ewing sarcoma or SDH-deficient solid tumor/Gastrointestinal Stromal Tumor (GIST).

This study involves taking a study drug called lurbinectedin. The overall goal of this study is to see if different doses of lurbinectedin are safe and effective at treating children and young adults with recurrent or relapsed solid tumors, including Ewing Sarcoma.

The goal of this observational study is to describe the safety and effectiveness of larotrectinib in patients with locally advanced or metastatic TRK fusion cancer for whom a decision to treat with larotrectinib has been made before enrollment. This study will enroll participants with any tumors harboring the NTRK gene fusion including Soft Tissue Sarcomas, Central Nervous System, Melanoma, and Thyroid cancers.

The purpose of this study is to test the safety and efficacy of the investigational drug called repotrectinib in children whose cancers have specific genetic changes (in the ALK, ROS1, or NTRK1-3 genes). This is the first study using this drug in children under 12 years of age. Repotrectinib is administered in capsule form or liquid suspension.

This study enrolls patients that have been diagnosed with SMARCB1 or SMARCB4 deficient cancer that has either come back (relapsed) or does not respond to therapy (is refractory) or have been newly diagnosed with a SMARCB1 or SMARCB4 deficient cancer that has no known standard treatment. This study involves taking study drugs called tiragolumab and atezolizumab. These drugs are a type of immunotherapy that try to make the immune system fight cancer. The purpose of the study is to learn more about the safety of tiragolumab in children and to see how well the combination of tiragolumab and atezolizumab works when given to children and adults with these types of tumors. This study has two parts. In Part A, participants will receive tiragolumab. In Part B, participants will receive both tiragolumab and atezolizumab.