HMOX1 and chronic obstructive pulmonary disease: An and colleagues reanalyzed the scRNA-seq data of peripheral blood mononuclear cells of COPD patients downloaded from the Gene Expression Omnibus (GEO) database and besides several experiments, they performed a correlation analysis between the expression and immune infiltration abundance of COPD immune-related genes and found high positive correlation of HO-1 in macrophages (74).