NCIS: Hilarious clip of Gibbs using his first tablet reveals episode guest star Tue May 11, 2021 at 5:14pm ET Mark Harmon will be featured in an important episode of NCIS called Unseen Improvements. Pic credit: CBS An NCIS sneak peek for the episode called Unseen Improvements has been revealed by the network. The clip provides a few laughs and a character we haven’t see in a while. On the last episode of NCIS, Gibbs testified against a criminal who was scheming to steal money from people in the Navy. Unfortunately, the defense attorney got Gibbs to admit that he crossed the line in his arrest of the dog murderer earlier in the season.