Study to Evaluate Adverse Events, Change in Disease Activity, and How Oral ABBV-101 Moves Through the Body in Adult Participants With B-Cell Malignancies

Inclusion Criteria:

For Dose Escalation (Part 1) only: Participants with documented diagnosis for one of the following 3L+ B-cell malignancies, from one of the following WHO-defined histologies (Swerdlow et al 2016):

Chronic lymphocytic leukemia (CLL)
Small lymphocytic lymphoma (SLL)
Chimeric antigen receptor T-cells (CAR-T)/hematopoietic cell transplant (HCT) relapsed/refractory (R/R) or ineligible diffuse large b-cell lymphoma (DLBCL) from the following histologies: DLBCL not otherwise specified (NOS) (germinal center B cell [GCB] and non-GCB DLBCL), T-cell/histiocyte-rich large B-cell lymphoma, primary mediastinal (thymic) large B-cell lymphoma, intravascular large B-cell lymphoma, anaplastic lymphoma kinase positive (ALK+) large B-cell lymphoma, high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, and high-grade B-cell lymphoma NOS.
Mantle cell lymphoma (MCL)
Follicular lymphoma [FL] (grades 1-3b)
Marginal zone lymphoma [MZL] (splenic, extranodal, and nodal)
Waldenström macroglobulinemia (WM)
Transformed indolent non-Hodgkin's lymphoma (iNHL)
For Dose Expansion (Part 2) only: Participants with documented diagnosis of CLL who are 3L+ including those with Bruton's tyrosine kinase (BTK) mutations or CAR-T/HCT R/R or ineligible non-GCB DLBCL who are 3L+ with histology based on criteria established by the World Health Organization (WHO).
Has an Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of 0, 1, or 2.
Participant has a life expectancy >= 12 weeks.
Prior Bruton's tyrosine kinase inhibitor (BTKi) is allowed.
Adequate hematologic, renal, and hepatic function per the protocol.
Participants with prior central nervous system (CNS) disease that have been effectively treated may be eligible.

Exclusion Criteria:

Previously treated with a Bruton's tyrosine kinase (BTK) degrader.
Known active CNS disease, or primary CNS lymphoma.
Uncontrolled active systemic infection, or active cytomegalovirus infection, known history of human immunodeficiency virus (HIV), active hepatitis B or C infection.