Given that the A549‐ACE2 cells do not express TMPRSS2 and that their infection was not only reduced upon ADAM17 knock‐out, but also with a lysosomal cathepsin inhibitor, we propose that ADAM17 acts in the lysosomal entry pathway, either at the plasma membrane just before endocytosis or after endocytosis (Fig 6A). The gene discussed is TMPRSS2; the disease is infection.