This study aims to evaluate the efficacy and safety of Relma-cel in the treatment of central nervous system lymphoma (CNSL), as well as its pharmacokinetic characteristics. Enrolled patients with relapsed/refractory (R/R) CNSL will receive Relma-cel infusion, followed by Tislelizumab treatment (200mg, IV, q4w, for 12 months) starting on day 35 after infusion. Bruton's tyrosine kinase (BTK) inhibitors will be used in combination as needed. The follow-up period will last for 4 years, monitoring drug safety, disease status, survival, and the pharmacokinetic characteristics of Relma-cel.