The goal of this phase 2 trial is to test the safety and efficacy of zanubrutinib and lenalidomide as maintenance therapy in patients with DLBCL.

The investigators will evaluate safety and efficacy of zanubrutinib and lenalidomide as maintenance therapy in patients with diffuse large B-cell lymphoma post complete remission and have completed planed courses of chemotherapy . Event-free survival (EFS), progression-free survival (PFS), overall survival (OS), adverse events (AEs) will be assessed.

Inclusion Criteria:

• Pathologically confirmed Diffuse Large B Cell Lymphoma according World Health Organization (WHO) classification;
• Patient is ≥ 18 years of age at the time of signing the informed consent form (ICF).
• Patient must understand and voluntarily sign an ICF prior to any study-specific assessments/procedures being conducted;
• Patient is willing and able to adhere to the study visit schedule and other protocol requirements;
• Patient has recieved complete remission and has completed planed courses of chemotherapy
• Meet the following lab criteria: Absolute Neutrophil Count (ANC) ≥ 1,5 x 10^9/L (≥ 1 x 10^9/L if bone marrow (BM) involvement by lymphoma)；Platelet ≥ 75 x 10^9/L (≥ 50 x 10^9/L if BM involvement by lymphoma)； Hemoglobin ≥ 8 g/dL. Anticipated life expectancy at least 3 months

Exclusion Criteria:

• Active or uncontrolled infections requiring systemic treatment within 14 days before enrollment;
• Any instability of systemic disease, including but not limited to severe cardiac, liver, kidney, or metabolic disease need therapy;
• Pregnant or lactating women