This study is for people with a specific type of cancer called metastatic Ewing's sarcoma (MES), which has spread widely in the body. The goal is to test a new treatment plan to see if it can help more people get better. The treatment is like a battle plan: first, hit the cancer hard to shrink it, then keep attacking to get rid of any tough cancer cells, and finally, use ongoing medicine to wipe out any leftover cells. This plan uses medicines known to work on newly diagnosed Ewing's sarcoma.

Eligibility: Participants must be over 1 year old and healthy enough for treatment. They must have a new diagnosis of MES or a similar cancer called CIC-rearranged sarcoma. They can't join if they have certain other health conditions or are pregnant.

• The study does not have an upper age limit, so adults and children can participate.
• Participants must commit to using two methods of birth control, or abstain, during and after the study.
• The study involves a series of treatments over a period of time, which requires regular hospital visits.