There are 3 essential chromatic passing notes that are abused and used in a lot of different types of music. These are the chromatic passing notes between 3 and 4, 4 and 5, and the 7and 8. These notes are not in key but go from a note that is in key to another note.
The most widely used scale in rock, blues and jazz music is the minor pentatonic scale. The term pentatonic refers to a five note scale. Picture the A pentatonic scale as an outline from which the 3 chromatic notes can be derived.
The chromatic passing note from the 4 and 5 is done at the 5th string, starting from the 5th fret going towards the 7th fret. It goes from D to D# to E with D# being the chromatic passing note. With the same pattern, the passing note between 7 and 8 is done at the 4th string and the 4 and 5 at the 3rd string. Chromatic passing notes are inessential notes that lie stepwise between two harmony notes.
These are the 3 basic chromatic passing notes in the A pentatonic scale. From these essential chromatic passing notes, you can make thousands of different variations. You can try using these patterns on another scale. Chromatic passing notes add more spice to the rhythm you wish to play.
Essential Chromatic Passing Notes:
This video is about the essential chromatic passing notes. Watch it on youtube.