RecruitingPhase 2Drug trialChidamide Combination With R-mini CHOP Followed by Chidamide+CD20 Maintenance in Elderly Newly Diagnosed MYC/BCL2+ DLBCLEfficacy and safety of chidamide in combination with the R-mini CHOP regimen, followed by chidamide plus CD20 monoclonal antibody as maintenance therapy, in elderly patients with newly diagnosed MYC/BCL2 double-expressor DLBCL.