ACE2 and viral infectious disease: At the molecular level, we found ACE2 anti‐expressed genes in most tissues and cells are highly enriched for virus infection pathways (Figure 3a), estrogen strongly and androgen moderately increase ACE2 expression in mouse and human tissues (Figure 2), whereas severe COVID‐19 induced IL‐2 and IL‐7 repress ACE2 expression in mouse T cells, and T2D reduced ACE2 expression and ACE2 expressing cells in human tissues (Figure 3).