STAT1 and opportunistic mycosis: To summarize, the susceptibility to endemic mycoses in CD40L deficiency, IL12Rβ1 deficiency, and IFN-γR1 deficiency highlights the critical role of the IL-12/IFN-γ crosstalk in macrophage activation and killing of these endemic fungi, while the deficiency of Th17 cells in patients with GOF STAT1 defect and AD hyper-IgE syndrome puts them at risk for both CMC and IFIs, and they frequently have CMC due to impaired mucosal immunity against C. albicans.