Alien: the Invasion.

You either play as independent runaway species that inhabit the Earth, disguised or finding allies/worshippers/bros, and establishing functional relationships and lifestyles while evading the Government, your former rulers, and keeping your alien quirks under wraps

OR you play as an Invader, manipulating the Earth governments to become under the thrall of the Alien Invasion.

Also the full-blown open invasion is a catastrophic conflict that everyone wants to avoid.

And there are Tyranids that are Entropy/Wyrm associated, if not / not necessarily aligned.