The blues scale is one of the first scales jazz musicians learn when they start to improvise. It looks like this:
What many beginners don’t realize yet, is that on a dominant 7 chord, or major chord of almost any kind, you can also use the blues scale from the relative minor. So if we’re on this same C7, we can also use the A blues scale:
Not only that, you can mix them together to great effect. Give it a try in your own playing.