It is important to understand that for chords and a melody to work at the same time, they must draw from the same pool of notes. This is the concept of keys and diatonic chords. In rock and blues, the chords in these songs tends to draw from the minor pentatonic scale, therefore it is this scale that we use to create lead lines, guitar solos and melodies.
It doesn’t even matter if the chords in a song are power chords or even full major chords. As long as the root notes of the minor pentatonic are in the chords, then the minor pentatonic in that key will work.