Way back when Justice League was meant to be two parts, with the second arriving in July 2019, the first was meant to set up the arrival of DC's biggest big-bad. Now, with Joss Whedon taking the reins and WB's superhero film slate in flux, that no longer appears to be the case.
Minor spoilers to follow.
It's been widely reported that the first Justice League film, the one coming out this November, was meant to end on a cliffhanger with Darkseid making his way to Earth. They've been setting up the arrival of Ya Boi D.S. in a number of ways, between Batman's bizarre dream sequence in Batman v Superman (the one where he sees a giant Omega symbol in the wasteland, not the one where Barry Allen, the guy known for being late, shows up asking "Am I too soon?"), Lex Luthor saying "Ding! Ding! Ding!" (don't ask) and the very inclusion of Steppenwolf as the villain in Justice League.
See, assuming they go with the widely known, inferior version of Steppenwolf (as opposed to bank-robbing werewolf Robert Stephen Banks), he's not only a minion of Darkseid, he's also his uncle. His whole deal is he helps Darkseid do stuff. Darkseid hated Highfather of the New Gods, so Steppsy went and murdered his wife. He's a right prick, innhe? It's safe to assume he's still coming to Earth to either prepare it for the arrival of his large adult nephew, or to nab the Mother Boxes for him to play with, so there's no way for this not to be a Darkeid-adjacent narrative. The plan, however, no longer seems to be to have Justice League feel like a Part One, so Darkseid probably won't play any active part, leaving the door open for other villains to show up in the DCEU until they decided to use him. Kind of like Thanos at the end of those other two superhero films Whedon directed.
That's a good thing! So the only real spoiler here is that it'll feel like a complete film. Let's hope whatever this ends up being is a good time. Lord knows this production needs the win.