Clinical trials revealed that the elevated levels of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-8, IL-6, and IL-1β in the serum and sputum of COPD patients, which is associated with the severity and exacerbation frequency of this disease [27,28,29]. Here, CXCL8 is linked to chronic obstructive pulmonary disease.