Leaves of Autumn
Over the years I’ve used the jazz standard Autumn Leaves to get folks improvising. It is a relatively simple tune and is nearly all in one key. You could use one major scale to improvise over all the chords. (More experienced players will obviously use many different approaches to the chord progression.)
The resources in this folder will help you learn new chords for the progression, show you how to play a chord-melody solo, and give you a nice medium tempo jam track to practice playing the chords, arpeggios, and improvising.