In response to these resistance issues and to mitigate side effects associated with ibrutinib, such as skin and dermatologic issues (45), bleeding, infections (46), headaches, and atrial fibrillation, newer generation BTK inhibitors, such as acalabrutinib and zanubrutinib, were developed and received FDA approval in 2017 and 2019, respectively (47). The gene discussed is BTK; the disease is infection.