Halo Wars 2 was released four years ago, and the last major update for the game was released in August 2020. In a new blog post at Halo Waypoint, 343 Industries now explains that the game won't have any more work done to it, and they go even further than that by also adding that there are "no current plans" for another Halo Wars:
"343 Industries has no current plans for further Halo Wars 2 work including content updates, balance patches, bringing the title to other platforms, or a new game in the series. We will, however, continue to monitor the game and ensure everything is working as expected."
Fortunately for all Halo Wars fans, they aren't completely shutting the door for new games further down the line:
"But, we're specifically never going to say never because, well, who knows what the future may bring."
Even if the development of a new Halo Wars would start today (which it clearly won't) , it still wouldn't be released until 2024 at the very earliest. So basically, don't expect more of this anytime soon.