Massive Entertainment held a Special Report livestream before the beta event kicks in, where they explained a few aspects of The Division 2 and also provided more insight into the mission-invading endgame enemy faction - the Black Tusks.
Massive Entertainment mentioned earlier that The Division 2 will transform once the players reach the endgame. One of those transformations is a direct result of the new enemy factions, called Black Tusk. They will waltz into the shrubbery version of Washington DC and take over some of the territories on the map.
You can be the good Samaritan that the Division agents are supposed to be and chase them out of those zones, but they will occupy some other place or return to invade the same zone later on. This is designed to give players a dynamic loop of events that should keep the endgame interesting for a while after the main campaign is done.
While a zone is under Black Tusk control, it will be changed as they take over control points. When this happens, players will be presented with a slew of new activities, although Massive Entertainment didn't specify what they are. It probably involves taking the zone back in various ways.
With that in mind, Black Tusks will not magically replace the other factions in the game. True Sons, Hyenas and the Outcasts will still attempt to control territories and better yet - they will fight Black Tusks if they encounter them. This should lead to three-way firefights that were encountered in the open world of The Division. You are most likely to replicate these scenarios next to the supply drops in the original game.
The developers finally revealed the name of the robotic dogs - they are called Warhounds and are just one part of Black Tusks' high tech arsenal. Their tendency to use electric equipment makes EMP grenades invaluable in the fight against this faction.
One of the most important points that Massive Entertainment made is that the higher difficulty from Black Tusks doesn't come due to them having more health or damage - it comes from tactical superiority and should offer dynamic firefights for the high-level agents.