Microsoft outlined their intentions for Xbox related content regarding Gamescom 2018 in Cologne Germany, revealing they will show new accessories and bundles along the way. There is no specifics as to what these accessories are though.
According to Microsoft's mini roadmap aimed at Gamescom, they will host an Inside Xbox session on 21 August 2018 where they will reveal the new accessories and bundles in question. The session will also update players on "features on upcoming titles" which may hint at Xbox One getting more functionality with or without the new accessories.
It's noteworthy that the announcement didn't originally mention "new bundles", but rather "new hardware" which flared up rumours about a potential reveal of the next generation of Xbox that Microsoft teased at E3 2018. Microsoft didn't entirely hide this change, as they slapped an "updated" description next to the title.
Fans might be expecting a revival of Kinect or another similar accessory but the next version of Xbox Elite wireless controller would be a safer bet, as it has already been leaked back in January 2018. There aren't many details on it yet, except the leaked images themselves, so it would make more sense if Microsoft showcased the controller at Gamescom.
There is also the fact that Microsoft announced a controller aimed at players with disabilities, named Xbox Adaptive controller, back in May 2018. Therefore, it's also possible the controller wll have the first field test during the upcoming event.
Xbox's presence at Gamescom won't be limited to just new hardware and bundle announcements though as Microsoft have announced an Xbox Booth with a lineup of 25 games to play, as well as Mixer booth and Xbox Gear Shop.
The Mixer booth will offer players a chance to play in an unnamed battle royale game, and Microsoft have stated that the players will have a chance to walk away with "big prizes". The gear shop will feature merchandise that will make fans walking adverts for the console, and
Microsoft didn't seem to hide this intention as they promote the shop by inviting players to "fly [their] gaming colours and show your fandom" by purchasing games, collectibles and apparel in the store.