This jazzy turnaround uses the classic vi-ii-V-I turnaround in the Key of C.
In the pickup measure, you’ll notice a passing tone (pt) that leads chromatically into the 5th (G) of Cmaj7.
I labeled this lick as a vi-ii-V-I turnaround, but the vi is not an Am7, rather it is an A7 (and it’s altered).
Altered chords simply change one or more chord tones by a 1/2 step. They’re used to step outside the diatonic chords slightly.
You’ll also notice that the lick highlights the non-diatonic C# in the A7 and the altered note, Bb.
The lick does not highlight the altered tone in the G7alt. Rather, it treats it as a G7 by using diatonic notes from the key of C.
This turnaround was recorded by Roman Garcia.