• Voluntary written informed consent obtained from the participant (or legal guardian) with good compliance expected throughout the study.

• All of the following conditions must be met:

∙ Age 2-75 years at informed consent; both sexes eligible. For minors (≤18 years), consent must be provided by a parent/legal guardian; minors able to sign must co-sign with their guardian.

‣ Histologically confirmed B-cell lymphoma per the 2024 v3 NCCN Clinical Practice Guidelines in Oncology: B-Cell Lymphomas.

‣ Prior therapy requirements:

• Failure to achieve PR after first-line therapy, OR relapse within 12 months after first-line therapy; or Relapsed/refractory after second-line therapy (one standard chemo-regimen + one salvage regimen).

• Prior regimens must have included anti-CD20 monoclonal antibody (unless documented CD20-negative tumor) and an anthracycline-containing regimen. In addition, at least one of the following must apply:

• i. Ineligible for autologous hematopoietic stem-cell transplantation (ASCT); ii. Refusal of ASCT; iii. Relapse after ASCT. d) Disease status at screening:

• • Relapse: progression after prior PR or CR.

• • Refractory: i. PD during/after last therapy, or best response ≤SD lasting \<6 months; OR ii. Relapse or progression after ASCT (biopsy-proven), including relapse/PD ≤12 months post-ASCT or lack of response (SD/PD) to salvage therapy after ASCT.

• Tumor tissue (archival or fresh) positive for CD19 by IHC; pathology report within 6 months preferred.

• ≥1 measurable lesion per Lugano 2014 response criteria.

• ECOG performance status 0-3.

• Adequate marrow reserve: ALC ≥0.3 × 10⁹/L; PLT ≥30 × 10⁹/L (transfusion permitted).

• Adequate organ function:

• • AST ≤3×ULN (≤5×ULN if tumor-related); ALT ≤3×ULN (≤5×ULN if tumor-related);• Total bilirubin ≤2×ULN (≤3×ULN with direct bilirubin ≤1.5×ULN for Gilbert's syndrome);• Serum creatinine ≤1.5×ULN or creatinine clearance ≥60 mL/min (Cockcroft-Gault);• Pulmonary: ≤Grade 1 dyspnea and SpO₂ \>91 % on room air;• LVEF ≥50 % by echocardiography;• INR ≤1.5×ULN and APTT ≤1.5×ULN.

• Women of child-bearing potential: negative serum/urine pregnancy test within 7 days before CAR-T infusion. All participants with reproductive potential must use effective contraception from screening through ≥12 months after CAR-T infusion.

• Adequate venous access for leukapheresis or repeated phlebotomy, with no contraindications to leukapheresis.

⁃ Estimated life expectancy \>3 months.