Experimentally, in a CS‐induced mouse COPD model, Spp1 was also found highly induced in the lung, and as shown by the single cell transcriptomics (Figure 1B), expression predominantly maps to CD11b (Itgam) positive lung macrophages, and only slightly to CD11c (Itgax) positive cells. Here, SPP1 is linked to chronic obstructive pulmonary disease.