The official Doom Twitter handle just Tweeted what it claims to be screenshots from the upcoming single-player DLC for Doom Eternal. Each screenshot showcases a different environment, indicating that the DLC will span across multiple regions. Bethesda is tight-lipped about the release date of said DLC, unfortunately.
https://www.notebookcheck.net/Doom-Eternal-s-single-player-DLC-screenshots-showcase-some-interesting-new-environments.464398.0.html