Rick Dennison and Gary Kubiak are disciples of Mike Shanahan.
Shanahan’s on a distant branch of the Bill Walsh coaching tree.
While Walsh’s core philosophy was “pass to set up the run” the Shanahan-Kubiak-Dennison offense first emphasizes the (zone) running game. It features a relatively high frequency of play-action, bootlegs, and the quarterback under center.
Easy, short completions are prioritized, as are yards after the catch. It’s a system predicated on precise timing and more “horizontal” passing than “vertical” passing, although deep shots are built in, typically off a play-action fake.
It’s a West Coast Offense.