This phase II trial studies the best approach to combine chemotherapy and radiation therapy (RT) based on the patient's response to induction chemotherapy in patients with non-germinomatous germ cell tumors (NGGCT) that have not spread to other parts of the brain or body (localized). This study has 2 goals: 1) optimizing radiation for patients who respond well to induction chemotherapy to diminish spinal cord relapses, 2) utilizing higher dose chemotherapy followed by conventional RT in patients who did not respond to induction chemotherapy. Chemotherapy drugs, such as carboplatin, etoposide, ifosfamide, and thiotepa, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Radiation therapy uses high energy x-rays or high-energy protons to kill tumor cells and shrink tumors. Studies have shown that patients with newly-diagnosed localized NGGCT, whose disease responds well to chemotherapy before receiving radiation therapy, are more likely to be free of the disease for a longer time than are patients for whom the chemotherapy does not efficiently eliminate or reduce the size of the tumor. The purpose of this study is to see how well the tumors respond to induction chemotherapy to decide what treatment to give next. Some patients will be given RT to the spine and a portion of the brain. Others will be given high dose chemotherapy and a stem cell transplant before RT to the whole brain and spine. Giving treatment based on the response to induction chemotherapy may lower the side effects of radiation in some patients and adjust the therapy to a more efficient one for other patients with localized NGGCT.

This phase III trial compares the effect of open thoracic surgery (thoracotomy) to thoracoscopic surgery (video-assisted thoracoscopic surgery or VATS) in treating patients with osteosarcoma that has spread to the lung (pulmonary metastases). Open thoracic surgery is a type of surgery done through a single larger incision (like a large cut) that goes between the ribs, opens up the chest, and removes the cancer. Thoracoscopy is a type of chest surgery where the doctor makes several small incisions and uses a small camera to help with removing the cancer. This trial is being done evaluate the two different surgery methods for patients with osteosarcoma that has spread to the lung to find out which is better.

The purpose of this study is to evaluate the efficacy of digoxin in treating relapsed non-SHH, non-WNT medulloblastoma in pediatric and young adult patients.

The purpose of this study is to determine if the addition of infusions of a type of immune cell called a "natural killer", or NK cell to the sarcoma chemotherapy regimen GEM/DOX (gemcitabine and docetaxel) can improve outcomes in people with childhood sarcomas that have relapsed or not responded to prior therapies.

The goals of this study are:

* To determine the safety and efficacy of the addition of adoptive transfer of universal donor, TGF imprinted (TGFi), expanded NK cells to the pediatric sarcoma salvage chemotherapeutic regimen gemcitabine/docetaxel (GEM/DOX) for treatment of relapsed and refractory pediatric sarcomas To determine the 6-month progression free survival achieved with this treatment in patients within cohorts of relapsed or refractory osteosarcoma, Ewing sarcoma, rhabdomyosarcoma and non-rhabdomyosarcoma soft tissue sarcoma.
* To identify toxicities related to treatment with GEM/DOX + TGFi expanded NK cells

Participants will receive study drugs that include chemotherapy and NK cells in cycles; each cycle is 21 days long and you can receive up to 8 cycles.

* Gemcitabine (GEM): via IV on Days 1 and 8
* Docetaxel (DOX): via IV on Day 8
* Prophylactic dexamethasone: Day 7-9 to prevent fluid retention and hypersensitivity reaction
* Peg-filgrastim (PEG-GCSF) or biosimilar: Day 9 to help your white blood cell recover and allow more chemotherapy to be given
* TGFi NK cells: via IV on Day 12