This study is a prospective, multicenter, single-arm clinical trial designed to evaluate the efficacy and safety of PD-1 inhibitor combined with tenofovir, chidamide, and lenalidomide in the treatment of relapsed or refractory Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs). The primary endpoint is the overall response rate (ORR) at 3 months, including complete response (CR) and partial response (PR). Secondary endpoints include overall survival (OS), progression-free survival (PFS), as well as safety and tolerability assessments. Eligible patients must have histologically confirmed EBV-positive B-cell or T/NK-cell LPDs with measurable lesions. This combination regimen targets multiple mechanisms, including inhibition of EBV replication, activation of the immune system, and enhancement of antitumor effects, aiming to provide an innovative therapeutic strategy for this challenging disease.