This is a single-arm, open-label, multicenter, dose-escalation, dose-expansion and efficacy-expansion phase I clinical study to evaluate the tolerability, safety, pharmacokinetics and preliminary antitumor activity of QLS2309 injection in patients with CD70+ relapsed/refractory hematologic malignancies.

Inclusion Criteria:

• 1. Subjects voluntarily participated and signed a written informed consent form
• Age ≥ 18 years, male or female
• ECOG performance status of 0-2
• Expected life-expectancy ≥ 3 months
• CD70+ relapsed/refractory hematologic malignancies
• Adequate organ function prior to QLS2309 administration
• Female patients with fertility must agree to the use of effective contraceptive methods during the study period and within 35 days of discontinuation of the trial drug.
• Male patients whose sexual partners are women of childbearing age must agree to use condoms during the study period and within 35 days of discontinuation of the trial drug during sexual intercourse.

Exclusion Criteria:

• Prior treatment with CD70-related antibodies, antibody-conjugated drugs (ADCs) or cell therapy products
• Symptomatic central nervous system (CNS) involvement, leptomeningeal metastasis or spinal cord compression caused by metastasis
• An active autoimmune diseases or known history of ≥ grade 3 irAE due to prior immunotherapy
• Known history of other active malignant tumor within 3 years
• Known history of chemotherapy, biological therapy, endocrine therapy, immunotherapy, monoclonal antibodies, etc. within 4 weeks
• Known history of active hepatitis B/C infection, HIV infection, Treponema pallidum infection