The purpose of this study is to determine the safety and tolerability of an experimental form of therapy, known as WU-CART-007 ("study drug"). WU-CART-007 uses immune cells, called T cells, that are genetically changed to identify cancer cells. In this study, T cells are collected from a healthy human donor and have been modified in a laboratory. If the genetically changed T cells recognize and attach to cancer cells, they may have the ability to kill those cancer cells.

Patients with T-cell Acute Lymphoblatic Leukemia (T-ALL) or Lymphoblastic Lymphoma (LBL), where the disease has come back (relapsed) or has not responded to treatment (refractory) may be eligible for the study.