In this first lick, Isaiah is rooted in the 9th position E major/C# minor pentatonic scale. It begins with a quick lick that can work well over any major I or minor vi chord.
Lets think of this lick in C# minor (though you can hear that it functions as well in E major). The first four notes can be understood as an enclosure below and above the C# (root), or as the major 3rd and perfect 5th of a G#7 chord (V), which would tonicize C# minor.
If you listen to George Benson's solo on The Borgia Stick, you can hear this exact idea at the end of the first phrase of his solo.
Another particularly slick part of the lick to digest is the rhythm. Notice how Isaiah emphasizes and hangs on to the dotted eighth feel at the start of the second bar. The result is a 3:2 hemiola where two different time feels occupy the same place in excellent rhythmic harmony. In the shed, I have had fun just playing the rhythm of this phrase over and over while allowing myself to not focus too much on the notes.