This is according to game director Marty Stratton who spoke to Polygon, and when asked about whether or not if there will be any DLC for the game in the future that focuses on single-player content, he replied in the affirmative. He also admits that 2016’s DOOM was a bit lacking in that area.
According to Stratton, “Honestly, if there’s one thing thing that I would like to go back and do different is to give people more of the [Doom] campaign post-launch. You know, more follow-up DLC from a campaign perspective. So we’re already planning that and I’m looking forward to it. We’ll talk about our whole plan.”
Of course things like when the DLC will be released, what it will contain, pricing, and more were not revealed, but this is something that gamers can look forward to, assuming that’s something they might be interested in. In the meantime DOOM Eternal has also yet to receive a release date, but it is currently planned for a release across multiple platforms including the PS4, Xbox One, Nintendo Switch, and the PC.