"The original ending of the movie, from what I understand, [Steppenwolf] was kind of playing the Silver Surfer role and Darkseid playing kind of the Galactus role, and the ending of the movie was a cliffhanger, and Justice League 2 was going to be Justice League vs. Darkseid. Darkseid arrives at Earth. This kind of down, dirty ending, and from what I understand, that has been completely removed. The ending ends the movie like a movie, it doesn't leave a huge cliffhanger now."
Originally, Justice League was announced as part one of a two part story, with DC villain Darkseidbeing set up as the main antagonist of Part Two. However, a lot has changed for the DCEU since then, as Warner Bros. is pivoting the tone and direction of its cinematic universe in the wake of the poor reception to its earlier films. Now it sounds like Justice League is following suit, as Darkseid is being held back (assumably for later down the line) and the movie will abandon a cliffhanger ending. This actually tracks with Joss Whedon's sensibilities, as he once said he didn't like the ending of Empire Strikes Back because it wasn't an ending and was just table setting for the next one.