ARTA-based Chemo-free Bridging/Maintenance Therapy in CAR-T Treatment for High-Risk R/R B-NHL Ineligible for HDCT and ASCT

Inclusion Criteria: * Willingly sign the informed consent form. * Age ≥ 18 years, any gender. * Histologically confirmed as B-cell non-Hodgkin lymphoma, including: * Diffuse large B-cell lymphoma (DLBCL) not otherwise specified (DLBCL-NOS) * Transformed follicular lymphoma (tFL) * High-grade B-cell lymphoma (HGBL) with MYC, BCL2, and/or BCL6 rearrangements * High-grade B-cell lymphoma not otherwise specified (HGBL-NOS) * Primary mediastinal large B-cell lymphoma (PMBL) * Follicular lymphoma grade 3b (FL3b) * Patients must have experienced at least one line of treatment for relapsed or refractory disease, meeting the following definitions: * Refractory: At least partial response (PR) after the last chemotherapy or relapse within 12 months after autologous transplantation. * Relapsed: Complete response (CR) after the last chemotherapy, followed by relapse before enrollment, or relapse or progression 12 months or longer after autologous transplantation. * Maximum tumor diameter (long axis) \> 4 cm. * Evaluator determines that the patient does not meet HDCT/ASCT criteria and meets at least one of the following: * Age ≥ 60 years * ECOG score = 2 * FEV1% or DLCO% ≤ 60% * LVEF \< 50% * Creatinine clearance \< 60 mL/min * ALT or AST \> 2× upper limit of normal (ULN) * Patient unwilling to receive high-dose chemotherapy and autologous stem cell transplantation. * Measurable target lesions: lymph nodes ≥ 15 mm in longest diameter, or extranodal lesions \> 10 mm. * Expected survival ≥ 12 weeks. * Laboratory tests must meet the following requirements at screening: * Lymphocyte count ≥ 0.1 × 10\^9/L * Hemoglobin ≥ 80 g/L * Platelets ≥ 50 × 10\^9/L * ALT/AST ≤ 5 × ULN and total bilirubin \< 2 × ULN * Creatinine clearance ≥ 30 mL/min * Lung function: ≤ CTCAE grade 1 dyspnea, and oxygen saturation (SpO2) ≥ 92% in room air. * LVEF ≥ 40% * Patients with primary central nervous system lymphoma are allowed (secondary CNS lymphoma is not allowed). * Sufficient venous access for apheresis, and no other contraindications for blood cell separation; female participants of childbearing potential must have a negative pregnancy test at screening. Exclusion Criteria: * History of allergy to any component of the cellular product or study treatment. * History of allogeneic hematopoietic stem cell transplantation. * History of organ transplantation. * Patients with active viral hepatitis requiring treatment, including: * Chronic HBV carriers with HBV DNA ≥ 500 IU/mL. * Positive HCV RNA in patients with positive HCV antibodies. * Positive HIV antibodies (HIV-Ab). * Positive Treponema pallidum antibodies (TP-Ab). * Elevated CMV DNA or EBV DNA above normal limits. * Clinical significance of CNS diseases * Presence of active primary central nervous system lymphoma. * Prior treatment with other genetically modified T-cell therapies or CAR-T therapies. * Severe genetic diseases or autoimmune diseases (e.g., systemic lupus erythematosus). * Thromboembolic events (e.g., myocardial infarction, pulmonary embolism, deep vein thrombosis) within 6 months prior to screening. * History of malignancies other than the indication for this trial within the last 5 years, except for in situ cancers (e.g., cervical, bladder, breast) or non-melanoma skin cancer. * Active infections requiring systemic treatment or uncontrolled infections. * Received lenalidomide, calcineurin inhibitors, chemotherapy (e.g., methotrexate, cyclophosphamide, ifosfamide, nitrogen mustard, or melphalan), mycophenolate, thalidomide, immunosuppressive antibodies (e.g., anti-TNF, anti-IL6, or anti-IL6R), radiation therapy, or any drug that binds FKBP12 (e.g., rapamycin, tacrolimus, everolimus) within 4 weeks prior to PBMC collection. * Pregnant or breastfeeding women, or men or women of childbearing potential unwilling to use contraception during the trial and for 2 years after RJ CAR-T 002 cell infusion. * Participation in other drug clinical trials (e.g., new drug trials, registrational studies, investigator-initiated trials) within 4 weeks prior to PBMC collection. * Researcher's judgment that the patient is unsuitable for the trial (e.g., poor compliance, drug abuse). * Vaccination with live or attenuated vaccines within 3 months prior to PBMC collection, or expected vaccination during the trial.