To access Battle.net games like Diablo IV or Overwatch 2 on your Xbox, you must link your accounts. This allows your progress, saves, and achievements to sync across platforms. How to Connect Your Console to Battle.net | Easy Guide
On a standard Xbox console, Battle.net works in the background through account linking rather than as a standalone app. However, for those on PC or specific handheld devices, the process is more direct.
While you cannot download a dedicated app directly onto an Xbox Series X|S or Xbox One console, you can fully integrate your Blizzard and Xbox accounts to play Blizzard games.