∙ Patients must meet all of the following inclusion criteria to be enrolled in this study:

• Patients with histopathologically confirmed DLBCL;

• Relapsed or refractory disease, defined as

‣ Disease relapse occurred after reaching disease remission (including complete response \[CR\] and partial response \[PR\]) at the end of the last treatment

⁃ Maintain stable disease (SD) or progressive disease (PD) at the end of the last treatment

• The age of patients ≥ 18 years old and ≤ 80 years old;

• The ECOG score was 0-2;

• Good organ function;

• Measurable lesions detected by radiological imaging were defined as the longest diameter of at least 1 lymph node lesion \> 1.5 cm, or the longest diameter of at least 1 extranodal lesion \> 1.0 cm, and at least 2 vertical diameters that could be accurately measured;

• Previously received ≥ 1 systemic therapy for lymphoma;

• Participants who relapse after autologous stem cell transplantation may be included, provided that the transplantation treatment has been more than 6 months from the screening;

• Fresh tumor biopsies or recent tumor tissue samples must be provided (within 2 years after study entry \[signed informed consent\]);

• Fertile women must agree to use efficient contraceptive measures throughout the study and at least 90 days after the last dose of study drug. The effective forms of birth control are defined as abstinence, hysterectomy, bilateral oophorectomy without menstrual bleeding for up to 6 months, intrauterine contraception, hormonal methods such as contraceptive injection, oral contraceptives; Fertile men must undergo sterilization vasectomy or use condoms, while their female partners use the above efficient contraceptive measures;

• Life expectancy ≥ 6 months;

• Sign written informed consent.