A Prospective Clinical Study of CD3-CD20 Bisspecific Antibody Based Therapy Combined With CD19-CAR T Cells in the Treatment of Relapsed Refractory B-cell Non-Hodgkin Lymphoma

"lymphocytes collection, and bispecific antibody-based therapy will be performed after successful Lymphocytes collection: Obinutuzumab:1000mg, cycle 1 day 1(C1D1) ,IV.~Glofitamab: 2.5 mg, C1D8; 10 mg,C1D15 ; 30 mg,C2D1 and C3D1, IV. It can be combined with other Immunization therapy during the use of bispecific antibodies according to the patient's condition.~On C4D1, the patient will be pretreated with fludarabine and cyclophosphamide (FC) regimen, and then infused with CART cells at a specific dose of 4 \* 1000000/Kg. Bispecific antibody maintenance therapy will be initiated on month 1/2/3 after CART infusion. In Phase1 bispecific maintenance therapy will be divided into three dose groups, using a 3 + 3 dose escalation design. In Phase 2, bispecific maintenance therapy will be used at the MTD dose of Phase 1."