This study is for patients with rare Central Nervous (brain or spine) tumors. The purpose of this study is to determine whether the experimental drug, nivolumab can shrink tumors in patients with rare Central Nervous System (brain or spine) tumors or increase the time it takes for these tumors to grow or spread throughout the body.

Glioblastoma adaptive, global, innovative learning environment or GBM AGILE trial is to identify effective therapies and improve survival for a type of brian cancer called glioblastoma (GBM) and to match effective therapies with adult patients with newly diagnosed or recurring glioblastoma. Eligible participants will have a 50/50 chance of taking either standard therapy medications or a medication not yet approved by the FDA called regorafenib during their standard of care treatment for GBM.