Mark Harmon left “NCIS” after almost 20 years as Leroy Jethro Gibbs to seek freshness and new challenges in his career. The pivotal moment occurred in the 19th season when Gibbs chose to stay in Alaska, not retiring but opting for a different path. Despite his exit, the show left room for a potential return, keeping Gibbs’ name in the credits. Season 20 introduced a new character, Shawn Murray, as Gibbs’s replacement. Harmon’s departure had a profound impact on fans, and there’s uncertainty about his return for Season 21. The show’s future remains unclear, leaving fans eager for updates on Gibbs’s fate in the post-Harmon era.