This is a phase I, interventional, single arm, open label, treatment study to evaluate the safety and tolerability of CD7 CAR-T cells in patients with relapsed and/or refractory, high risk hematologic malignancies.

T-acute lymphoblast leukemia (T-ALL) accounts for 15-20% of all ALL cases. It is a neoplastic lymphoid leukemia characterized by the proliferation of immature precursor T cells. T-ALL is a highly aggressive tumor. Adults need intensive chemotherapy, and the cure rate is <50%, even with stem cell transplantation. The prognosis is also very poor. The combined chemotherapy has significantly improved the prognosis of T-acute lymphoblast leukemia/lymphoma. However, once the disease appears to be relapsed/refractory, there is limited treatment options, and the overall prognosis is extremely poor. Therefore, exploring safe and effective treatments is a critical unmet medical need. Since 95% of T-ALLs express CD7, this might provide an effective targeting approach for the vast majority of T-ALL cases.

Inclusion Criteria:

• 1. Signed written informed consent; Patients volunteer to participate in the clinical trial; 2. Diagnosis is mainly based on the World Health Organization (WHO) 2008; 3. Complete remission cannot be achieved after induction therapy; recurrence occurs after completion remission; the burden of leukemic blasts in the peripheral blood or bone marrow is greater than 5%; 4. Leukemic blast cells express CD7 (CD7 positive by flow cytometry or immunohistochemistry ≥70%); 5. The expected survival period is greater than 12 weeks; 6. ECOG score ≤2; 7. Age 2-60 years old; 8. HGB≥70g/L (can be transfused); 9. Total bilirubin does not exceed 3 times the upper limit of normal value, and AST and ALT do not exceed 5 times the upper limit of normal value.

Exclusion Criteria:

• 1. Patients declining to consent for treatment 2. Prior solid organ transplantation 3. One of the following cardiac issues: atrial fibrillation; myocardial infarction within the past 12 months; prolonged QT syndrome or secondary QT prolongation; clinically significant pericardial effusion; cardiac insufficiency NYHA (New York Heart Association) III or IV; 4. History of severe pulmonary dysfunction diseases; 5. Severe infection or persistent infection cannot be effectively controlled; 6. Severe autoimmune disease or congenital immunodeficiency; 7. Active hepatitis; 8. Human immunodeficiency virus (HIV) infection; 9. Clinically significant viral infections, or uncontrollable viral reactivation, including EBV (Epstein-Barr virus).