[en] Highlights: • HAXPES activities at the HIKE end station at the KMC1 beamline at BESSY II. • Review of HAXPES. • Review of research areas covered by HIKE. - Abstract: In the present work we review a number of research directions addressed at the HIKE end-station at the BESSY II storage ring at the Helmholtz-Zentrum Berlin, HZB, using hard X-ray photoelectron spectroscopy (HAXPES). The emphasis of this review is on the specific properties of the technique, which are required in order to address different scientific questions at the HIKE beamline.