One molecule, calprotectin, produced by activated neutrophils (Silvin et al,2020) can act as a ligand for TLR4 and promote NF‐κB activation (Riva et al,2012) and the secretion of multiple COVID‐19‐associated downstream inflammatory cytokines, i.e., IL‐6 and IP‐10 (Curtale et al,2013; Young et al,2020). Here, TLR4 is linked to COVID-19.