Via Archie Miller's wikipedia page....which is a lot better than I would have done to describe what it is that he does.
Miller employs a structured transition offense intended to open up games, create foul trouble for opponents, and score before the defense can get set. His offensive approach has been called "one of the most complete transition offensive systems you will find." He frequently uses a "Phoenix fast break" with players pushing the ball off of rebounds and turnovers in a flexible system that can take on a variety of alignments. He will modify the Phoenix break based on personnel to accommodate five guards or two post players on the floor at once. If an opponent scores, Miller employs a "Carolina transition offense" to create scoring opportunities which flow right into a motion offense.
The identity of Miller’s teams are rooted in defense. He employs a "pack line defense," which is a variation of man-to-man defense invented by Dick Bennett at Wisconsin and also employed by Tony Bennett at Virginia, and Tom Izzo at Michigan State, among others. Instead of the off-ball defenders pressuring their player and denying the pass, everyone except the player guarding the ball must be inside an imaginary line 16 feet from the rim. At all times a defender pressures the player with the basketball, while the other four defenders play in gap/help positions. However, if the offensive player picks up the dribble, all players go out and deny looking for the steal. The pack line defense is intended to discourage penetration, getting inside the paint, and forces opponents to win with a well executed offense and good outside shooting.
You can see the fingerprints in the analytics of their fast offensive pace, their drawn out defense times, and allowing an above average number of 3pt attempts