STAT3 and COVID-19: The hub targets including EGFR, PIK3R1, PIK3CA, STAT3, MAPK1, etc., and the biological signaling pathways including HIF-1 signaling pathway, FoxO signaling pathway, T cell receptor signaling pathway, PI3K-Akt signaling pathway, etc. involved in these targets are considered to play a critical role in 1,25(OH)2D against COVID-19/DM.