Acute T Cell Lymphoblastic Leukemia

The goal of this clinical trial is to learn if haploidentical hematopoietic cell transplantation combined with an unrelated cord blood unit (haplo-cord HCT) works to treat acute T cell lymphoblastic leukemia (T-ALL). It will also learn about the safety of the transplantation. The main questions it aims to answer are: Dose co-infusion of cord blood in haploidentical hematopoietic cell transplantation (haplo-HCT) lower the rate of relapse? What medical problems do participants have when having haplo-cord HCT? Researchers will compare haplo-cord HCT to haplo-HCT to see if haplo-cord HCT works to treat T-ALL. Participants will be infused an unrelated cord blood unit at the same day of haploidentical graft infusion.