The long-running navy crime-fighting show "NCIS" has been renewed for its 21st season, originally scheduled for 2023-2024. However, due to strikes by SAG-AFTRA and WGA, the release date has been delayed until 2024. In the meantime, viewers can enjoy the new spin-off, "NCIS: Sydney." When Season 21 does air, it will break records as the longest-running scripted series on CBS and will also mark the franchise's 1,000th overall episode. Despite cast changes and challenges, "NCIS" has proven its staying power in the competitive world of primetime dramas.