All this means is that it will probably be a small-scale "Alien-esque" story about Genestealers trying to steal our genes like awa mentioned.
It's gonna be 'Nids. That's basically their only option...except for digging back into the Nurgle well for the 10000000000000000 time in a 40k adaptation as the only Chaos god/faction that both has a distinct identity (Khorne is conceptually boring for a show, and Tzeentch is too "behind the scenes" to adapt well except into a very poltically charged show, which they aren't gonna do) and is "safe for tv" because Slaanesh is too horny.