Iibrutinib is a potent, small molecule irreversible BTKi with wide-ranging anti-tumor effects including interference with B-cell activation, reversal of CD4+ Th2 cells on Th1 cells shift, and inhibition of MDSCs expressing BTK (resulting in reduction in immune escape cytokines production) and MDSC migration and proliferation [23,57]. The gene discussed is IBTK; the disease is neoplasm.