In NCIS Season 11 Episode 19 (Crescent City: Part II) a character called Wendell Hobbs plays a bluesy tune on an electronic keyboard. It may well just be a made up ditty for the show (basic 12 bar blues stuff), but I'd love to know if it's from an actual song (and an idea of the exact genre if possible).
I cannot find anything from hours of searching varying keywords. If you have Amazon Prime Video, it's S11E19 at around 11:16.