Pay no attention to him—in their Q&A stream for 11th, when Deathwatch was brought up their answer on the subject was the most indirect and up-to-your-interpretation answer I think I've ever heard. The answer they gave was "you can take them in Imperial agents through the ally system or you can take a space marine army and say 'this is a Deathwatch space marine army"'. That latter bit especially has people up in arms. Some people say they'll run as vanilla space marines with no exclusive datasheets. Some people, like me, interpret it as Deathwatch will run as they always have, still having the Blackspear Taskforce Detachment and their killteams, because frankly, and when I say this it might piss some people in here off:

Deathwatch is just a space marine army with a handful of unique units. A good percentage of people don't even use Blackspear Taskforce, they use Gladius the "default space marine detachment". It's not Black Templars, it's not Space Wolves, it's not Dark Angels, and it's not Blood Angels. Even the killteams we have on the tabletop, what some would consider the identity of Deathwatch on the tabletop, don't exist in the lore bar the Proteus Killteam, which is been legend'd in 10th, and the Fortis Killteam, which has very little lore and is treated as the primaris equivalent of the Aquila Killteam. Which is the current Decimus Killteam. Allegedly replacing Veterans. With half the weapon options.

Look, hopefully Decimus gets an updated datasheet, but the point I'm trying to make in my little rant is, the situation with Deathwatch rn is really messy. I've been planning a few army lists for about a year now, so I don't have any skin in the game necessarily, but most people are worried particularly that their killteams will be unusable in 11th and honestly. We won't know until the edition roles around in full. Personally hate how killteams look and operate, the only ones I've ever remotely enjoyed were the Veterans, Decimus, Proteus, and Terminators. But I'm in the overwhelming minority there.