Zanubrutinib and Lenalidomide as Maintenance Therapy in DLBCL

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