When Jesse Eisenberg was asked about returning to the role of Lex Luthor in future Justice League. Luthor orchestrated the conflict between the titular heroes in Batman v Superman: Dawn of Justice, and he returned for a brief post-credits scene in Justice League in what appeared to be a setup for a villain team that would oppose the League in the next movie.
Batman v Superman: Dawn of Justice was panned by critics for many reasons, but Superman comics was replaced by someone more akin to the Joker. The version of Luthor that appeared in the Justice League post-credits sequence was much closer to his comic book counterpart, but a lot of damage had already been done to the DCEU's reputation, some of which wasn't Eisenberg's fault, so there were doubts that he would be returning to the role in the future.
Eisenberg was recently interviewed alongside Woody Harrelson during the promotional tour for Venom movie franchise. Harrelson's answer was cut off by Eisenberg, who seemed doubtful that he would be coming back to the role of Luthor in comparison to Harrelson returning as Carnage.
"Different venues, I will say very confidently. His will be kind of a movie that people, like, go to and mine will be, like, in my living room, you know, that people occasionally go to, but it's mostly one at a time."
The future prospects of the DCEU have been in flux over the past few years. The harsh critical response to Batman v Superman: Dawn of Justice and the disappointing box office take from Justice League seemed to spell the end for the DCEU in its current form, but the success of Ben Affleck no longer playing Batman and Henry Cavill's status as Superman still in question, which has cast doubt on Eisenberg's potential return to the franchise.
The post-credits scene of Justice League suggested that Luthor still had a big role to play in future DCEU films and Eisenberg expressed a desire to play Luthor again back in 2018, but he seems confident than this won't be happening again. The DCEU has seen a lot of shake-ups and it's possible that future films will want to distance themselves from Batman v Superman: Dawn of Justice and Justice League, which could involve recasting the role of Luthor.
Source: ComicBookMovie.com