Several studies have reported increased expression of CXCL9 (34–36), as well as CXCL10 and CXCL11 (16), in severe COVID-19 patients, three co-expressed chemokines that were found increased in the COPD patients in our study (Figures 2B and 7). This evidence concerns the gene CXCL10 and chronic obstructive pulmonary disease.