Inclusion Criteria - Participant must be 18 years or older at the time of signing the informed consent form (ICF). - Histologically confirmed primary central nervous system (CNS) lymphoma (PCNSL) prior to screening, as assessed by local pathology. - Transplant-ineligible based on physician's assessment and meeting at least one of the following criteria: age ≥65 years or HCT-CI (Hematopoietic Cell Transplantation-specific Comorbidity Index) score ≥3. - Participant must be suitable, per investigator, to receive a high dose methotrexate (HD-MTX) based treatment regimen. - Prior to signing ICF, anti-cancer therapy for the treatment of PCNSL must only include standard of care regimens, with or without corticosteroids given for disease-related symptoms. - Prior to ICF signature, participant's disease must be sensitive to prior high-dose methotrexate-based regimens, as demonstrated by a complete response (CR, no remaining signs of PCNSL) or a partial response (PR, signs of PNCSL mostly gone) per Investigator's assessment, based on the International Primary CNS Lymphoma Collaborative Group (IPCG) criteria. - Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2. - Individuals of childbearing potential (IOCBP) must have a negative highly sensitive pregnancy test within 24 hours prior to the start of study intervention. Exclusion Criteria - Participant has a diagnosis of secondary CNS lymphoma due to systemic disease. - Primary intraocular lymphoma (PIOL)/ Primary vitreoretinal lymphoma (PVRL) and isolated cerebrospinal fluid (CSF) disease. - Any significant medical condition including the presence of laboratory abnormalities, which places the participant at unacceptable risk if he/she was to participate in the study based on investigator's judgement. - History of another primary malignancy that has not been in remission for ≥2 years. - Prior treatment with CAR T-cell or any other gene therapy product that utilizes human genome-editing technology. - History of or active human immunodeficiency virus (HIV). - Active hepatitis B or active hepatitis C. - Active autoimmune disease requiring immunosuppressive therapy. - Other protocol-defined Inclusion/Exclusion criteria apply.