Chemoimmunotherapy for ALK+ Relapsed/Refractory ALCL

Children, adolescents, and young adults (CAYA) with relapsed/refractory (R/R) high-risk ALK+ Anaplastic Large Cell Lymphoma (ALCL) have a low incidence of overall survival. This clinical trial will investigate if a new FDA approved medication called Nivolumab (NIVO) (which is a checkpoint blockade immunotherapy) combined with chemotherapy based on the patients risk status to get the patient into the best response possible. Then patients will receive lower doses of chemoimmunotherapy and allogeneic stem cell transplantation (stem cells from another person). The investigators this this new treatment will improve survival rates in this high-risk population of patients.