Short Answer
No. Crimson Desert is not available on Xbox Game Pass. The game did not launch as a day-one Game Pass title, and Pearl Abyss has not announced any plans to bring it to the service.
Could It Come Later?
Pearl Abyss has specifically stated that Crimson Desert is not coming to Game Pass on day one. The phrasing leaves open the possibility that the game could join the service at a later date, but there has been no official confirmation or timeline for that. Many third-party games eventually appear on Game Pass months or years after release, so it remains a possibility but not a certainty.
Xbox Play Anywhere
While Crimson Desert is not on Game Pass, it does support Xbox Play Anywhere. If you purchase the game through the Xbox Store, you get access on both Xbox consoles and PC (via the Microsoft Store/Xbox app) with shared save data between those two platforms. This is a one-time purchase benefit, not a subscription perk.
Current Purchase Options
Crimson Desert is available as a full-price purchase ($69.99 USD) on Steam, Epic Games Store, Microsoft Store, PlayStation Store, and the Xbox Store.