Chronic exposure to cigarette smoke or other combustible organic matter is the strongest known risk factor for the development of chronic obstructive pulmonary disease (COPD). However, inflammation and lung damage persist in many patients with COPD despite smoking cessation. This session will highlight recent basic and translational studies that address why inflammation is disproportionally increased in COPD patients compared to smokers without COPD and why disease progression persists in some COPD patients even after smoking cessation.