This study is for people with certain blood cancers called r/r B-cell malignancies (like NHL or CLL). It is a Phase 1 trial, which means it's the first time this treatment, called SC291, is being tested in humans. The treatment is given through an IV (a tube that goes into your vein) after some chemotherapy medicines called cyclophosphamide and fludarabine. The study checks if SC291 is safe, how it works against tumors, and how the body reacts.

NHL stands for Non-Hodgkin's Lymphoma and CLL is Chronic Lymphocytic Leukemia. These are types of cancer that affect white blood cells. The study involves two parts: the first to find a safe dose, and the second to expand testing to more people.

To join, you need to be between 18-80 years old and have had at least two prior cancer treatments. You can't join if you've had certain treatments before or have other specific health problems.

• The study has two parts and involves multiple visits.
• Participants will receive SC291 via IV after chemotherapy.
• Potential risks and benefits will be closely monitored.