• Participants ≥18 years of age at screening visit

• Participants with documented and confirmed diagnosis of any of the below diseases:

‣ B-cell CLL according to International Workshop on CLL (iwCLL) criteria and RAI staging of intermediate (1 and 2) or high (3 and 4)

⁃ MM according to the International Myeloma Working Group criteria (IMWG), R-ISS stage II or, III; or

⁃ Histologically confirmed diagnosis of B-Cell NHL, Stage III or above (IV, Progressive/refractory, or recurrent/relapsed stage) according to the Lugano Classification.

• Participants with HGG with IgG levels less than 5 g/L.

• Participants with documented history of at least one severe bacterial infection (bacterial or viral) or recurrent bacterial/viral infections (that is., ≥ 3 infections) within 12 months before the screening visit. Severe bacterial/viral infections ≥ Grade 3 (as defined by Common Terminology Criteria for Adverse Events \[CTCAE\] Grades).