Chronic airway inflammation and infiltration of immune cells are critical characteristics of COPD, and subsequently remodel the bronchus, resulting in the development of COPD.[22] In addition, a study investigated the expression of peripheral blood expression immune cells in COPD patients and revealed the expression of several immune cells increased, such as CD3+ CD8+ T cells.[23] In the study, we applied a 2-sample MR analysis to analyze the causal role of COPD on 731 immune cell traits. Here, CD8A is linked to chronic obstructive pulmonary disease.