Blizzard revealed not one, not two, but three expansions for World of Warcraft at BlizzCon 2023. All three of these expansions are connected and will be contained within a larger story called World of Warcraft: The Worldsoul Saga.
The first expansion is titled The War Within and it's planned to launch at an unscheduled date in 2024. The other two expansions contained in The Worldsoul Saga are called Midnight and The Last Titan. During the showcase, World of Warcraft creative director Chris Metzen described the expansion as "the culmination of the first 20 years of our storytelling."
An official description of The War Within reads: "Prepare to descend beneath the surface of Azeroth to explore subterranean worlds full of hidden wonders, earn the trust of the new Earthen allied race, and face an ancient evil lurking in the darkness."
You can take a look at the trailer for The War Within below: