This is a single-center, single-arm, prospective study aimed at evaluating the efficacy and safety of orelabrutinib combined with an induction regimen followed by monotherapy maintenance in patients with MCD subtype diffuse large B-cell lymphoma (DLBCL). The primary endpoint is the 2-year progression-free survival (PFS) rate; secondary endpoints include overall response rate (ORR), complete response rate (CRR), overall survival (OS), and treatment-related adverse events (TRAEs). The study plans to enroll 66 patients.