We first screened the expression of ACE2 and TMPRSS2 in various human cell lines relevant to SARS‐CoV‐2 infection and COVID‐19, including several airway cell lines and endothelial cells, and explored whether ACE2 and/or TMPRSS2 could be induced by culturing the cells for longer and/or on transmembrane inserts, either submerged or at an ALI. The gene discussed is TMPRSS2; the disease is COVID-19.