RecruitingPhase 2Drug trialPD-1 Inhibitor Combined With Rituximab, Methotrexate, and Orelabrutinib (PD-1i+RMO) for Newly Diagnosed PCNSL and SCNSL.This is a multicenter, open-label, single-arm, prospective clinical study of PD-1 inhibitor combined with rituximab, methotrexate, and orelabrutinib (PD-1i+RMO) in the treatment of newly diagnosed primary central nervous system lymphoma (ND-PCNSL) and secondary central nervous system lymphoma (SCNSL). The primary endpoint is 1-year progression-free survival (PFS).