High-energy Astronomy Searches for Particle Dark Matter

A primary mission for high-energy astronomy observatories has been the search for emission of photons associated with the annihilation or decay of dark matter. I review the status of candidate signals in the X-ray and gamma ray, including the Galactic Center Excess in gamma-ray observations by Fermi-LAT as well as the enigmatic 3.55 keV unidentified line observed toward multiple sources. I will present the dynamical information that can be probed by XRISM and future X-ray observatories, as well as what an optimal dark matter X-ray observatory would look like. Lastly, I will present the rich connections of light dark matter models with both small-scale structure probes of dark matter with JWST and the sensitivity of X-ray observatories to the same mass-energy scale.