Ubisoft presented Ghost Recon Breakpoint at E3 if that's what you call the new pre-rendered cinematics but the gameplay wasn't shown at the presentation. It later popped up on YouTube though and AI teammates were confirmed for solo players.
Ubisoft's Ghost Recon Breakpoint E3 presentation was could be summed up as a series of pre-rendered, cringe-inducing cinematic trailers. First, it's Cole Walker yapping about Wolves' symbolism and then it's Nomad rambling about Ghost symbolism.
In both cases, their statements turned out to be incorrect as Walker implies the world totally needs a bunch of spec ops soldiers going rogue and taking over an island filled with the most advanced weaponry in the world while Nomad says Ghosts never die. Weaver, Midas and Holt beg to differ.
Anyway, Ubisoft didn't officially show any gameplay during the presentation but they did confirm solo players will, in fact, get AI teammates, an idea that was not on the table initially but it seems like they heard the fans' pleas. It remains to be seen if they will manage to properly implement them until 4 October 2019 or if they will be shoehorned in.
There was, however, a lot of gameplay shown as IGN staff teamed up with the developers and took over an outpost where they had a mission to extract a scientist. It proved to have more cinematic moments than Wildlands where the only cutscenes happened in safe houses with Bowman.
Considering that it was only regular security guarding the building initially and Wolves appeared afterwards, it is hinted they will have the same dynamic as Santa Blanca and Unidad, where the latter are a bit more formidable since they have an additional mechanic or two up their sleeve.
We also got to see a bit more of Auroa which is scarcely populated on the account of being a private island, rather than an actual country. Ubisoft almost certainly opted for this imaginary place in Ghost Recon Breakpoint to avoid conflicts if a real-life country didn't like their depiction and decided to sue them.