Trial Drug: Bendamustine

The purpose of this study is to evaluate the efficacy and safety of nemtabrutinib compared to investigator’s choice of fludarabine plus cyclophosphamide plus rituximab (FCR) or bendamustine plus rituximab (BR) in participants with previously untreated CLL/SLL without 17p deletion and/or tumor protein (TP) 53 mutation. The primary hypothesis is that nemtabrutinib is superior to FCR/BR with respect to progression-free survival (PFS).