  The impact of electroweak Sudakov logarithms on the endpoint of the photon
spectrum for wino dark matter annihilation was studied intensively over the
last several years. In this work, we extend these results to Higgsino dark
matter $\chi_1^0$. We achieve NLL' resummation accuracy for narrow and
intermediate spectral energy resolutions, of order $m_W^2 / m_\chi$ and $m_W$,
respectively. This is the most accurate prediction to date for the yield of
high-energy $\gamma$-rays from $\chi_1^0 \chi_1^0 \to \gamma + X$ annihilation
for the energy resolutions realized by current and next-generation telescopes.
We also discuss for the first time the effect of power corrections in
$m_W/m_\chi$ in this context and argue why they are not sizeable.
