A Study to Compare the Efficacy and Safety of Lisocabtagene Maraleucel vs Investigator's Choice Options in Adult Participants With Relapsed or Refractory Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma, Whose Disease Has Failed Treatment With Both BTKi and BCL2i Therapies

Inclusion Criteria * Must have what doctors call measurable disease, which will be evaluated before each participant take part of the study. * Must have received both a BTKi and a BCL2i treatment, and their disease must have come back or not responded to treatment, or they must not have been able to tolerate the side-effects of the BTKi and/or BCL2i treatment(s). * Must also have an ECOG performance score of 0 or 1, which means they are able to carry out their normal daily activities without any problems. Exclusion Criteria * Heart problems. * Bleeding disorders. * Active cancer in their brain. * Other reasons include:. i) Having certain treatments in the past. ii) Having certain infections that are not under control. iii) Having certain brain conditions. \- Other protocol-defined Inclusion/Exclusion criteria apply.