It looks doubtful Kiefer Sutherland will be returning to 24 in the near future. 24 followed the adventures of CTU agent Jack Bauer, who across various seasons had to work overtime to prevent terrorist attacks, government conspiracies and try – and usually fail – to keep his loved ones safe. The show was an intense, addictive ride at its peak, and it pioneered the real-time format, where each episode was an hour within a single day.
Eventually, the show started repeating itself and losing viewers, so the showrunners called it quits with season eight. A feature film version was trapped in development hell for years until it was decided to resurrect the show as a miniseries dubbed Live Another Day. This 12-episode series found Jack confronting terrorists in London, but Kiefer Sutherland publicly declared he was done with the show when the season wrapped. Instead, 2017 brought 24: Legacy, a spinoff starring Corey Hawkins as another highly stressed out agent chasing terrorists. The revival struggled in the ratings and was canceled after one season.
It appears the current plan for 24 is to move away from terrorism as a theme and turn it into a legal thriller, with recent reports suggesting it could follow a female prosecutor trying to get her client off death row. FOX Chairman Gary Newman confirmed in a Deadline report the show is exploring new angles but doesn't rule out returning to the standard formula:
I think terrorism is uniquely suited for 24 because the timeliness and urgency is built in. You could be in the medical field or the legal field where a clock is ticking and something has to happen. But I wouldn’t bet against terrorism as a theme.
Fans hoping Jack Bauer will come back to save the day probably shouldn't hold their breaths, with Newman stating "Clearly, Kiefer (Sutherland) is not coming back… If he were available and wanted to, that would be pretty good. But we think that the franchise is still really valid.”
While Sutherland hasn't ruled out ever returning to 24, he's currently focused on other projects like Designated Survivor. A major issue is that 24 has run out of interesting stories to explore for Jack Bauer. The character has survived ungodly amounts of punishment and bereavement over the various seasons, and it doesn't feel like there's much more he can suffer. In fact, Sutherland confirmed an alternate ending for Live Another Day would have seen Jack sacrifice himself, though the idea was ultimately rejected in case the network wanted another season.
It could be interesting to see the show explore other genres or ticking clock scenarios. The showrunners always claimed the real-time format itself was the star of 24, and one potential angle the show might take is that of an anthology, with each series exploring a new storyline. Of course, the issue here is that Jack Bauer has become the icon of the series, so without Kiefer Sutherland's involvement, viewers may not be interested in more.
It sounds like even Fox isn't sure what to do with 24 next, so it might be awhile before anything happens with the franchise.