This study is testing a drug called F01 to see if it is safe and tolerable for people with **non-Hodgkin's lymphoma** that has come back or not responded to treatment. Non-Hodgkin's lymphoma is a type of cancer that affects the lymphatic system, which is part of the immune system. The study is in **Phase I**, which means it is early in the testing process to make sure the drug is safe. About 55 people will participate. The study has two parts: **dose escalation** and **dose expansion**. In dose escalation, different doses of F01 are tested to find the safest and most effective dose. Dose expansion involves more people to confirm the findings. The whole process helps researchers figure out the best dose to use in future studies. **Key Points:** - Participants may have had previous treatments like CAR T cell therapy. - The study involves multiple visits to a clinic over an extended period. - Participants must meet specific health criteria to join, like having good blood counts and organ function. This study will help doctors understand if F01 can be an effective treatment option for non-Hodgkin's lymphoma in the future.