Recent advances in understanding the inflammatory pathways underlying COPD have led to the development of biologic agents targeting critical cytokines and their receptors, including IL-4 receptor (IL-4R), IL-5, IL-5 receptor (IL-5R), IL-33, ST2, and thymic stromal lymphopoietin (TSLP). The gene discussed is IL4R; the disease is chronic obstructive pulmonary disease.