Studio Wildcard seems to be having a nightmare bringing Ark: Survival Ascended to consoles, because recently the developer announced that the game would be late on PS5 and instead debuting at the end of November, and now the Xbox Series version has also missed its planned release date.
Thankfully, there is a light at the end of the tunnel for this one, as the developer has noted that the game will still be launching on Xbox later this week, and that it was only delayed due to it taking longer than expected to pass through the console certification process.
There is no firm timeline on when Ark: Survival Ascended will come to Xbox Series consoles (and Windows users for that matter), but the hope is for "later this week".