Bungie CEO Pete Parsons has announced he's stepping down after over 20 years with the company, and he'll be handing his responsibilities over to another long-time Bungie staffer.
In an announcement on the official Bungie website, Parsons says he's "decided to pass the torch" and that now is the "right time for a new beginning", but he doesn't elaborate on his reasons for leaving any further than that.
Parsons will be handing his CEO role over to Justin Truman, who previously served as Destiny 2's General Manager and the chief development officer of Bungie as a whole. It sounds as though the transition will be instantaneous, since no other date is given.

Truman begins his own message by reminding fans of his credentials; he worked as a coder for the original Destiny and served as a designer on Destiny 2, crafting many systems for the game (including the endgame mechanisms, which he says he got "terribly wrong" at launch).
He's also been helping Bungie to develop Marathon, so it's fair to say he's been across everything the studio has worked on for the last ten years or so. It's easy to see why Parsons picked Truman for a successor.
Truman inherits a Bungie that is, to put it charitably, struggling somewhat. Marathon's rollout isn't exactly going smoothly; the game was originally due to launch in September, but was delayed to an unspecified point in the future following lackluster feedback from the first closed alpha test.
The extraction shooter also found itself in hot water back in May, when it was revealed that artwork used in the game had been taken from an online artist without permission or compensation (which, incidentally, is not the first time Bungie has been caught doing something like this).

That's all in addition to the fact that the latest Destiny 2 expansion, The Edge of Fate, hasn't exactly been rapturously received, so it looks like Truman has his work cut out if he wants to turn Bungie's fortunes around. We'll have to wait and see whether he achieves that goal.