English: Ibrutinib (IBR) leads to CLL cell mobilization from the nodal compartment, making CLL cells more accessible to chemotherapy and anti-CD20 antibody in peripheral blood. Lower left diagram depicts intracellular mechanism of combination. Anti-CD20 antibody along with chemotherapy induces apoptosis and immunologic cell death, while ibrutinib affects proliferation, survival, and migration of B cells. Chemotherapeutic agents such as fludarabine are well known to cause depletion of all T cell subsets, thereby reducing negative trophic signals between T cells and CLL cells. This figure was created with BioRender.com. BCR, B cell receptor.