Chidamide, Lenalidomide, and Rituximab in Newly Diagnosed Elderly/unFit DE-DLBCL

To evaluate the efficacy and safety of Chidamide in combination with lenalidomide and rituximab (CR2) as induction therapy, followed by chidamide maintenance in responding patients with newly diagnosed elderly/unfit double-expressor DLBCL.

Inclusion Criteria: * Histopathologically confirmed, previously untreated DLBCL; * Age ≥70 years, or ≥60 years with comorbidities (including reduced left ventricular ejection fraction, history of myocardial infarction \[\>6 months prior to enrollment\], exertional angina, arrhythmia \[Grade ≤2\], hypertension or diabetes requiring treatment), or ECOG PS ≥2 deemed ineligible for standard chemotherapy; * At least one measurable lesion, defined as: Nodal lesion: Longest diameter \>1.5 cm, or Extranodal lesion: Longest diameter \>1.0 cm, with two perpendicular dimensions accurately measurable; * ECOG PS ≤3; * Estimated life expectancy ≥3 months * MYC and BCL2 protein co-expression confirmed by immunohistochemistry (double-expressor lymphoma) * Voluntary participation; full understanding of the study with signed informed consent; willingness and ability to comply with all study procedures Exclusion Criteria: * Pregnant or lactating women, and patients of childbearing potential unwilling to use contraception; * Recipients of organ transplantation; * Uncontrolled coagulopathy or active bleeding; * Uncontrolled cardiocerebrovascular diseases (including LVEF \1.5×ULN; * HBV infection: HBsAg-positive patients: Eligible if HBV DNA \