RecruitingPhase 2ProcedureStudy of Novel Therapies for Young People With Recurrent/Progressive Atypical Teratoid Rhabdoid Tumor (ATRT)This is a multi-treatment arm study that will be conducted through the Pacific Pediatric Neuro-oncology Consortium (PNOC).The study will assess the safety and efficacy of novel therapies and combinatorial strategies for participants with recurrent or progressive ATRT.