RecruitingPhase 1Drug trialLoncastuximab and Roflumilast Added to R-CHOP (Lo-(Rituximab and Roflumilast) RR-CHOP) for Naïve High-Risk Diffuse Large B-cell Lymphoma (DLBCL)This study is developed by the investigator and is a, phase I, single arm, clinical trial that will enroll subjects with untreated diffuse large B-cell lymphoma (DLCBL) at high risk for poor outcome. The types of treatments given will be shared with participants. The aims are: 1. To assess the safety and how well the participants tolerate the treatment 2. Assess the response of the tumor to treatment to estimate complete response 3. Assess the response of the tumor to treatment to estimate progression-free survival