Targeting CD19/CD20 Dual-targeted Cell in Patients With Relapsed/Refractory B-cell Non-Hodgkin Lymphoma

Inclusion Criteria: 1. Subjects have fully understood the possible risks and benefits of participating in this study, are willing to follow and able to complete all trial procedures and have signed informed consent. 2. Aged 18-75 years (inclusive). 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 4. Histologically confirmed B-cell non-Hodgkin Lymphoma that expresses at least one of CD19/CD20. 5. At least one evaluable tumor lesion according to Lugano 2014 criteria. 6. Response to prior therapy is consistent with one of the following: 1） Patients with B-NHL who are primary refractory and are unsuitable or unwilling to receive autologous CAR-T cell therapy; 2） primary refractory is defined as the best response to first-line treatment being SD or PD; 3） Relapse within 12 months after achieving CR with first-line chemotherapy and immunotherapy; 7. Life expectancy≥ 3 months 8. Women of childbearing potential must have a negative highly sensitive serum pregnancy test (β-human chorionic gonadotropin \[β-hCG\]) at screening and before the first administration of cyclophosphamide and fludarabine treatment; Exclusion Criteria: 1. Diagnosed with or treated for other invasive malignancies besides B-cell non-Hodgkin lymphoma. 2. Active acute or chronic graft-versus-host disease (GVHD), except for grade 1 skin involvement; or requiring immunosuppressive treatment for GVHD within 4 weeks prior to enrollment; 3. Active CNS involvement (symptomatic or positive cerebrospinal fluid or imaging data), prior CNS infiltration but currently in remission (asymptomatic and negative cerebrospinal fluid and/or imaging data) is eligible; 4. Significant bleeding tendency, such as gastrointestinal bleeding, hemorrhagic cystitis, coagulopathy. 5. Chronic diseases treated with steroids or other immunosuppressants. The following situations are excluded: use of topical, ocular, intra-articular, intranasal, and inhaled corticosteroids; short-term use of corticosteroids for prophylaxis; 6. Severe underlying diseases, such as: - Evidence of severe active viral, bacterial infections, or uncontrolled systemic fungal infections; - Active or unstable autoimmune diseases, or autoimmune diseases within the past 3 years with potential for relapse; 7. Breastfeeding women;