This study is exploring two immunotherapy drugs, nivolumab and ipilimumab, for treating specific childhood and young adult cancers that are INI1-negative, meaning the cancer cells lack a certain protein. These drugs are not yet approved by the U.S. Food and Drug Administration (FDA) for these particular cancers, but they have been tested for safety in children. The aim is to see if the drugs help fight these cancers.

Eligibility: Participants should have certain types of tumors and have tried other standard treatments without success. They must also have good overall health and not be pregnant.

• The study involves taking the drugs together to see if they work against the cancer.
• Participants will need to meet specific health criteria to join.
• The trial is for those who have no other treatment options and have INI1-negative tumors.