  Using the enhanced symmetry in the near-horizon region of the near-extremal
dyonic Kerr-Newman (KN) black hole in the (A)dS space, we find the exact
solutions for dyonic charged scalar field in terms of the hypergeometric
function and explicitly compute the Schwinger effect for the emission of
electric and/or magnetic charges. The emission formula confirms a universal
factorization of the Schwinger formula in the AdS$_2$ and another Schwinger
formula in the two-dimensional Rindler space determined by the effective
temperature and the Hawking temperature with the chemical potentials of
electric and/or magnetic charges and the angular momentum. The emission of the
same species of charges from the KN black hole is enhanced in the AdS boundary
while it is suppressed in the dS boundary. In addition, the dragging of
particles in the KN black hole diminishes the emission of charges in both AdS
and dS spaces. The AdS geometry of near-horizon gives the Breitenloher-Freedman
(BF) bound, within which the stability of dyonic KN black holes is guaranteed
against both the emission of charges and Hawking radiation.
