It looks like the story of Doom Eternal will be continuing on in the form of DLC. Earlier today, the official Doom Twitter account shared two screenshots of campaign DLC. The first screenshot looks to be Urdak, Doom Eternal's version of Heaven, inhabited by the angelic Makyr race. The last time the Doom Slayer visited the location, he sort of upended the entire thing, leading to its now ruined status.
The second location looks to be some sort of naval base. That could be a Union Aerospace Corporation (UAC) base, but it lacks the ubiquitous UAC logos plastered all over everything. It's likely another Armored Response Coalition (ARC) complex, like the one you visit during Doom Eternal's campaign.
More single-player campaign DLC is an interesting move for Doom Eternal. Doom (2016)'s DLC was all related to the multiplayer side of that game. Some also disliked the increased focus on story for Doom Eternal, given that the Doom Slayer is more of an elemental force of destruction rather than a real character. The publisher has promised two single-player DLC releases as part of the Year One Pass for Doom Eternal. It's unknown if these screenshots are both from the first DLC, or two different releases.
Doom Eternal has been the focus of a break-up between id Software and the game's composer, Mick Gordon. Fans noted that Doom Eternal's soundtrack was very compressed, leading Gordon to explain that he only mixed a handful of the songs. Those statements were followed by Doom Eternal co-director and executive producer Marty Stratton stating that Gordon was late in delivering the soundtrack, forcing the studio to come up with alternate options. Stratton said that Gordon signed off on the use of the alternative tracks and said id Software was open to releasing additional songs from Gordon. Despite that, Gordon's music won't be in the DLC.
"As for the immediate future, we are at the point of moving on and won't be working with Mick on the DLC we currently have in production," Stratton said at the time. "As I've mentioned, his music is incredible, he is a rare talent, and I hope he wins many awards for his contribution to DOOM Eternal at the end of the year. [...] Our team has enjoyed this creative collaboration a great deal and we know Mick will continue to delight fans for many years ahead."
We still don't know when this DLC will release, given the current worldwide situation.