Artist and Halo fan Skykillerr has uploaded a video showcasing Warhammer 40,000: Space Marine 2 modded to let you play as a Sangheili "Elite" alien from the Halo franchise. At the time of writing, Skykillerr does not appear to have shared the mod widely for public use.
Skykillerr specifically ported in a white "Ultra" Elite from Halo: Reach, which makes for a nice pun with the "Ultramarine" branch of the Adeptus Astartes portrayed in the Space Marine series.
