RecruitingPhase 1Drug trialThe Safety, Tolerability, and Efficacy of IBR900 Cell Injection in Relapsed/Refractory B-cell Non Hodgkin LymphomaThis is an open label clinical study: Phase Ia is a dose escalation phase, evaluating the safety, tolerability, RP2D, PK characteristics, and preliminary efficacy of IBR900 cell injection in the treatment of relapsed/refractory B-cell non Hodgkin lymphoma (NHL); Phase Ib is the dose expansion stage, which is divided into two parts: monotherapy expansion (queue 1) and combination expansion (queue 2). The monotherapy expansion part evaluates the safety, tolerability, and preliminary efficacy of IBR900 cell injection in the treatment of relapsed/refractory CD20 positive B-cell non Hodgkin lymphoma, while the combination expansion part evaluates the safety, tolerability, and preliminary efficacy of IBR900 cell injection combined with CD20 monoclonal antibodies in the treatment of relapsed/refractory CD20 positive B-cell non Hodgkin lymphoma.