Mr. Brightside by The Killers is played in the key of Db at a intermediate difficulty level, originally released in the 2000s. It uses 3 chords — Db Gb Ab — arranged in the I-IV-V progression.
About the I-IV-V progression
The I-IV-V progression uses the three primary chords of the key — nothing else. It's the harmonic foundation of blues, folk, country, and early rock and roll. Learning to switch between these three chords fluently in every key is a fundamental milestone for beginner guitarists.
Playing in the key of Db
Db major uses Db, Gb, and Ab — three barre chords. Guitarists almost always capo up to a friendlier key (capo 1st fret plus C-major shapes works cleanly).
Related songs
More songs using the I-IV-V progression
Learn to play Mr. Brightside by The Killers on guitar. It sits in the key of Db and uses the I-IV-V progression with the chords Db Gb Ab.