They definitely compliment each other well.
KDK are fast, but lack long-range firepower. Renegades are slow, but provide lots of shooting.
Rapier Laser Destroyers are absolutely brutal. Thudd Guns and Earthshakers are also solid. If you don't want to have an expensive kitted out Daemonkin
HQ, you could put a base Herald in with the artillery to gain blood tithe whenever they kill stuff, too.
If you run Renegades as your primary detachment you can unlock the Ordnance Tyrant (from Siege of Vraks) and unlimited Zombies, which are,
imo, one of the best troop choices in the game. Note that
IA:13 has a 0-1 limit on Zombies, while the Vraks list has no such limit.
If you run them as your secondary force, a secondary
CAD with 9 Rapier Laser destroyers and some ObSec troops should work well. The Purge detachment (Siege of Vraks) also gives you 4 Heavy Support slots, which is solid.
Edit: I did a tournament report earlier this year from when I brought my Renegade/
KDK force to a tournament
here if you would be interested in hearing how it's worked for me.