CD7-CAR-T Cells in Pediatric Relapsed/Refractory CD7+ T-ALL/LL

This trial tests a type of immune cell therapy called CAR-T cells for children with a rare and aggressive blood cancer called T-cell acute lymphoblastic leukemia or lymphoma (T-ALL/LL) that has come back or stopped responding to treatment. The CAR-T cells are engineered to target a protein called CD7 found on these cancer cells. **You may be eligible if...** - You are a child or young person with CD7-positive T-ALL or T-lymphoma - Your cancer has relapsed (come back) or is refractory (not responding) after at least one round of standard treatment - You have relapsed after a bone marrow transplant (at least 100 days post-transplant, no active graft-versus-host disease) - You may have cancer spread to the brain/spinal fluid or other sites outside the bone marrow **You may NOT be eligible if...** - Your cancer cells do not express the CD7 protein (less than 98%) - You are on immunosuppressants within 30 days - You have active graft-versus-host disease after transplant Talk to your doctor to see if this trial is right for you.