This study is testing a new treatment for kids and young adults (ages 6 to 25) with difficult-to-treat brain cancer. It uses a combination of drugs, including ibrutinib and indoximod, which help the immune system fight cancer. Ibrutinib blocks a protein called BTK (Bruton's tyrosine Kinase), and indoximod blocks IDO (indoleamine 2,3-dioxygenase). The goal is to find the safest dose of ibrutinib when used with other chemotherapy drugs.

To participate, patients need to have specific types of brain cancer and meet health requirements such as good liver and kidney function. They must be able to swallow pills and not be pregnant or breastfeeding. Some previous treatments are allowed, but patients must have finished them a certain time before joining.

• Study Duration: This is a phase 1 trial, meaning it focuses on finding the right dose and is one of the early steps in testing a treatment.
• Health Requirements: Participants must meet specific health conditions, like being able to swallow pills and having good organ function.
• Eligibility: Patients with certain brain cancers who have tried other treatments may be eligible.