• Have confirmed diagnosis of CLL/SLL as defined by iwCLL 2018 criteria.

• Part 1: Have received prior CLL/SLL treatment

• Have received at least 1, but not more than 3 lines of prior treatment for CLL/SLL

• Have received a covalent BTK inhibitor

• Part 2: Have received no prior treatment for CLL/SLL

‣ Part 1 - Known 17p deletion status (positive or negative)

⁃ Part 2 - Must have 17p deletion (positive)

• Have a requirement for therapy consistent with iwCLL 2018 criteria for initiation of therapy

• Capable of swallowing oral study medication.

• Have an Eastern Cooperative Oncology Group Performance Status (ECOG) score of 0 to 2.