This is a prospective, single-arm, open-label exploratory clinical study to evaluate the safety, tolerability, pharmacokinetics and anti-tumor efficacy profiles of LUCAR-20SP, an allogenic CAR-T cell therapy in subjects with relapsed/refractory B-cell non-Hodgkin lymphoma. Patients who meet the eligibility criteria will receive LUCAR-20SP infusion. The study will include the following sequential stages: screening, pre-treatment (lymphodepleting chemotherapy), treatment and follow-up.