RecruitingPhase 1Drug trialZanubrutinib in Combination With Pola-R-CHP and High-dose Methotrexate in Patients With Secondary CNS LymphomaThe purpose of this study is to is to determine the effects (good and bad) of Zanubrutinib in Combination with Pola-R-CHP and High-dose Methotrexate in patients with Secondary Central Nervous System (CNS) Lymphoma.