  The singlet scalar Higgs portal model provides one of the simplest
explanations of dark matter in our Universe. Its Higgs resonant region,
$m_\text{DM}\approx m_h/2$, has gained particular attention, being able to
reconcile the tension between the relic density measurement and direct
detection constraints. Interestingly, this region is also preferred as an
explanation of the Fermi-LAT $\gamma$-ray Galactic center excess. We perform a
detailed study of this model using $\gamma$-ray data from the Galactic center
and from dwarf spheroidal galaxies and combine them with cosmic-ray antiproton
data from the AMS-02 experiment that shows a compatible excess. In the
calculation of the relic density, we take into account effects of early kinetic
decoupling relevant for resonant annihilation. The model provides excellent
fits to the astrophysical data either in the case the dark matter candidate
constitutes all or a subdominant fraction of the observed relic density. We
show projections for future direct detection and collider experiments to probe
these scenarios.
