Spayse Muhreen fans, unite!
► LinkSet in the Gathering Storm era, it features both Necrons and Tyranids, though whether that's just in the skirmish/multiplayer modes or if they play an actual story role hasn't been announced. We should get a good dose of Primarch Guilliman though, by the looks of things!
It also looks like Imperial Navy ships will see greater visual variety in this outing, depending on their affiliation - Adeptus Mechanicus skins were shown off in the trailer, alongside what look like different classes of ship, or at least Mechanicus analogs to Navy ships.
Other than that, expect all the usual suspects (Orks, Eldar & Chaos) to return in the story, presumably joined by all the other races in the non-story modes.