More Destiny is coming, one way or another.
An image of several rusted shells of cars and some Guardians walking amongst them in Destiny 2.

A new report from Forbes says that Bungie is likely developing Destiny 3. The article, penned by Paul Tassi, is based off of a throwaway Reddit account and may not exactly be the most reliable of sources. Still, that throwaway account did reveal the Prismatic subclass months before Bungie announced it themselves yesterday.

That original message from February says that Bungie "is working on a system called prism that will allow players to mix and match abilities from different subclasses." This is, in essence, exactly what the Prismatic subclass coming with Destiny 2: The Final Shape will be. This Prismatic subclass was one of the major reveals during yesterday's livestream presentation for The Final Shape. If this "prism" idea from that leak was legitimate, what else did the leaker say that should be examined under a new light?

The Reddit user went on to say that Destiny 3 is in development and is being made under the codename "Payback." The leaker suggests that Destiny 3 would do away with classes. Instead, Destiny 3 would "allow any character to spec into any ability." With this in mind, it does seem like the Prismatic subclass idea, where you can mix and match abilities within subclasses, is the precursor to this more open class system supposedly in the works for Destiny 3.

The leaker again chimed in on Reddit just yesterday to add some additional context to Payback.

I've seen some speculation on this front and want to set the record straight. Codename Payback does not mean we lose in the Final Shape, or after the 3 episodes (though, tbf, I know nothing more than any of you about the episodes). The internal codename of D3 is not a reference to any story events. Rather, Codename Payback refers to Bungie getting payback against themselves by creating something they hope everyone will love. I do not know if there are any plans for Destiny 2 items to carry over into Destiny 3.
The leaker says that their sources include some former Bungie employees. This means that while the information shared by them could have been true at one point in time, it may not be true now or in the future. In other words, plans can change and Destiny 3 may not end up happening at all.

Right now, we know for a fact that Bungie is working on Marathon. We also know that Bungie plans to release at least three Episodes for Destiny 2 following the June release of The Final Shape. Destiny 2: The Final Shape is out on June 4. Between now and June 4th, players can freely partake of the new Into the Light content, which adds a new social hub, retooled weapons, and more.