This great OST by Tim Wynn can be found on Spotify. There's a clear theme that's used for most of the tracks, in slight variations. My favorite is the squad loadout, when you prepare for a mission. Just the perfect backdrop to get ready!

One of the great things of the soundtrack is that you'll never notice it as looping in the background too much, even though the songs aren't that long. They blend in perfectly with the gameplay, while still being interesting to listen to.

It also helps that the main theme that is used throughout the songs is pretty good itself, giving the whole OST a strong consistency.