Chimeric antigen receptor (CAR) T-cell therapy offers options for pediatric patients with relapsed or refractory acute lymphoblastic leukemia, but it comes with a unique set of side effects that can range from mild to severe. As the primary patient providers, oncology nurses are often the first to identify signs and symptoms of adverse events and acute changes in patients’ status. Understanding what to watch for can improve outcomes and help nurses deliver safe, effective care.