"Hybrid" approach mixes dedicated servers and some peer-to-peer communication.

With Destiny 2 moving the franchise to the PC for the first time, a lot of players were hoping Activision would use dedicated servers to ensure stability and reliability. The company mentioned last week that those hopes for a dedicated server wouldn't be fulfilled, but Destiny 2 Engineering Lead Mat Segur says the game's hybrid server model is a bit more complex than that announcements suggests.
Unlike the original Destiny, where matches were hosted on one player's console, "every activity in Destiny 2 is hosted by one of our servers," Segur said in a Bungie blog post yesterday. "That means you will never again suffer a host migration during your Raid attempt or Trials match."

But those servers won't handle all the data for every player in the game. While "the server is authoritative over how the game progresses... each player is authoritative over their own movement and abilities," Segur continued. "This allows us to give players the feeling of immediacy in all their moving and shooting—no matter where they live and no matter whom they choose to play with."

That peer-to-peer element could allow unscrupulous players to try to gain an advantage by sending fake data about their game state to the server, of course. That kind of problem recently led to rampant cheating in Ubisoft's The Division, which had a severely exploitable, client-centric networking model.

Segur promises that "our security Ninjas have spent several years building a plan for how to engage with this new and vibrant community" and that "a variety of top-secret strategies to ensure that the life of a cheater in Destiny 2 PC will be nasty, brutish, and short." They could take a lesson there from Ubisoft, which eventually started issuing permanent bans for The Division cheaters after one infraction.
While Segur said he can't promise that lag-induced glitches will be completely eliminated in Destiny 2, he says this server model should lead to a definite reduction. We'll see if the game lives up to that promise when the beta test launches this summer.