For example, Sun T. et al. [78] conducted a careful analysis of 3128 patients with a laboratory diagnosis of COVID-19: skin rashes were present in 52 patients (1.66%) and single-cell RNA sequencing analysis demonstrated the colocalization of ACE2 and TMPRSS2 in the keratinocytes of the granular layer. The gene discussed is TMPRSS2; the disease is Skin rash.