CD8+ T cell-deficient mice are protected against lung inflammation and emphysema induced by cigarette smoke exposure (Maeno et al., 2007) whereas the expression of molecules linked to tissue destruction, such as perforin, granzyme B, and ADAM15, correlate with disease severity (Freeman et al., 2010; Wang et al., 2020), suggesting CD8+ T cells implication in lung inflammation and destruction in COPD. The gene discussed is CD8A; the disease is chronic obstructive pulmonary disease.