Autologous HuCART19 T Cells Manufactured Using the CliniMACS Prodigy Platform for Pediatric B-ALL (huCART19 Prodigy)

This study is testing a CAR T-cell therapy — a treatment where a patient's own immune cells are re-engineered to attack cancer — for children with B-cell Acute Lymphoblastic Leukemia (B-ALL) or B-cell lymphoma that has come back or has not responded to standard chemotherapy. **You may be eligible if...** - You are a child or young adult with B-cell ALL or B-cell lymphoma confirmed to have the CD19 protein on cancer cells - Your cancer has relapsed (come back) or is refractory (not responding) to at least one or two rounds of prior therapy - You have not previously received CAR T-cell therapy (Cohort A), OR your prior CAR T-cell therapy did not work or your cancer came back (Cohort B) - You are ineligible for or have already had a stem cell transplant **You may NOT be eligible if...** - Your cancer cells do not carry the CD19 protein - You do not meet the specific relapse or treatment failure definitions - You have active, uncontrolled infections or organ failure Talk to your doctor to see if this trial is right for you.