ACE2 and COVID-19: One of the reasons for the lack of progress in elucidating the endothelial pathology in COVID‐19 is that the mouse models of severe COVID‐19, which are indispensable research tools, have not been commonly used until recently, and the common cultured ECs used for the research have low expression of the SARS‐CoV‐2 receptor, angiotensin‐converting enzyme II (ACE2).