• Patients with diffuse large B-cell lymphoma (DLBCL) confirmed by histopathology/cytology using the 2022 World Health Organization (WHO) Classification of Diseases;

• Patients with R/R DLBCL who have received at least two lines of systemic treatment;

• Age range: 18-70 years old, male or female not limited;

• When the disease recurs or is difficult to treat, there are assessable lesions (lymph node diameter ≥ 1.0cm; or skin lesions assessable by physical examination);

• Expected lifespan\>3 months;

• No previous transplantation treatment has been performed;

• ECOG score 0-1 points;

• Appropriate organ function:

• Cardiac function: ejection fraction ≥ 50%, asymptomatic arrhythmia; Liver function: alanine aminotransferase and aspartate aminotransferase ≤ 2 times the upper limit of normal, total bilirubin\<2 times the upper limit of normal; Renal function: serum creatinine clearance rate ≥ 80 mL/min, creatinine\<160 umol/l; Pulmonary function: Without oxygen inhalation, SPO2\>90%, FEV1, FVC, and DLCO ≥ 50% predicted values;

• Adequate bone marrow reserve is defined as:

• Hemoglobin ≥ 9g/dL, Platelet count ≥ 70 × 10 \^ 9/L, The absolute value of neutrophils is ≥ 1.0 × 10 \^ 9/L, If accompanied by bone marrow invasion, platelet count ≥ 50 × 10 \^ 9/L, absolute neutrophil count ≥ 0.75 × 10 \^ 9/L, The number of CD34+cells is ≥ 2.0 × 109/kg.

⁃ The patient has the ability to understand and is willing to provide written informed consent.

⁃ Subjects with fertility or potential for fertility must be willing to undergo contraception from the date of registration in this study until the study follow-up period.