A Study on Limiting Treatment Time With Acalabrutinib Combined With Obinutuzumab in People With CLL or SLL

Inclusion Criteria: * Signed informed consent form (ICF). Legally Authorized Representatives are permitted. * Ability and willingness to comply with requirements of the study protocol * ≥ 18 years-old * Have documented previously untreated CLL or SLL per WHO criteria and require treatment per iwCLL guidelines * ECOG performance status of 0, 1, or 2, with no deterioration over the previous 2 weeks prior to baseline or day of first dosing * Participants must have adequate organ and marrow function as defined below: * Total bilirubin ≤ 1.5 times upper limit of normal (ULN), unless there is a disease involvement of the liver, hemolysis, or a known history of Gilbert's disease. * Hemoglobin ≥ 8 g/dL without transfusion support, unless anemia is due to marrow involvement of CLL. * Absolute neutrophil count (ANC) ≥ 1.0 x 10\^9/L. * AST and ALT ≤ 2.5 times the ULN. * Creatinine clearance (CrCl) \> 30 mL/min as calculated using modified Cockcroft- Gault or MDRD Formula * PT/INR ≤ 2 times the ULN and aPTT ≤ 2 times the ULN unless the elevation in PT/INR or aPTT is solely attributable to direct oral anticoagulant. * Platelet count without transfusion support must be ≥ 50,000 cells/mm3 or ≥ 30,000 cells/mm\^3 in subjects with documented bone marrow involvement, as determined locally. * For women of childbearing potential: Agreement to remain abstinent (refrain from heterosexual intercourse) or use a highly effective contraceptive method (failure rate of \< 1%) per year duri…