• Patients older than 18 years and 65 years or less.

• Diagnosis of CLL meeting the iwCLL 2018 criteria.

• Total CIRS \<6, creatinine clearance \>30 ml/min \[Cockcroft-Gault\]) and ECOG performance status of 0-1.

• No prior treatment.

• Patients with unmutated IGHV, and, or TP53 mutation assessed by an ERIC certified laboratory, and, or deletion 17p assessed by FISH analysis.

• Active disease meeting at least 1 of the iwCLL 2018 criteria for treatment requirement.

• Adequate hematologic parameters unless due to disease under study:

‣ Absolute neutrophil count (ANC) ≥1.0 x 109/L unless neutropenia is clearly due to disease under study (per investigator discretion)

⁃ Platelet count ≥ 75,000/mm3 - OR - Platelet count ≥ 20,000/mm3 if thrombocytopenia is clearly due to disease under study (per investigator discretion)

⁃ Hemoglobin ≥9.0 g/dL unless anemia is clearly due to marrow involvement of CLL (per investigator discretion)

• Adequate renal and hepatic function, per laboratory reference range at screening as follows:

‣ AST/SGOT, ALT/SGPT ≤2.0 x ULN

⁃ Total bilirubin ≤1.5 x ULN unless considered secondary to Gilbert's syndrome, in which case ≤3 x ULN

• QT-interval corrected according to Fridericias formula (QTcF) ≤450 milliseconds (ms).

⁃ For females of childbearing potential, a negative serum pregnancy test within 7 days of study treatment.

⁃ For female patients of childbearing potential, agreement to use highly effective form(s) of contraception (i.e., one that results in a low failure rate \[\<1% per year\] when used consistently and correctly) or remain abstinent (refrain from heterosexual intercourse) during the treatment period and to continue its use for 90 days after the last dose of zanubrutinib AND 30 days after the last dose of venetoclax AND for 18 months after the last dose of obinutuzumab (whichever date is later). For men with a female partner of childbearing potential or a pregnant female partner: agreement to remain abstinent (refrain from heterosexual intercourse) or use a condom during the treatment period and to continue its use for 90 days after the last dose of zanubrutinib, or venetoclax AND for 18 months after the last dose of obinutuzumab (whichever date is later).

⁃ A signed informed consent document indicating that they understand the purpose of and the procedures required for the study, including biomarkers, and are willing to participate in the study.

⁃ Ability and willingness to comply with the requirements of the study protocol.