Given the similarity between asthma and COPD in terms of eosinophilic airway inflammation, several randomized controlled trials (RCTs) have studied the efficacy and safety of anti-IL-5 treatment in eosinophilic COPD patients (Brightling et al., 2014; Dasgupta et al., 2017; Sciurba et al., 2018; Criner et al., 2019). Here, IL5 is linked to chronic obstructive pulmonary disease.