Knives Out 3 could have a fun story to tell with Joseph Gordon-Levitt. Dating back to director Rian Johnson's debut with 2005's Brick, the actor and filmmaker have enjoyed a fruitful partnership. Gordon-Levitt has been involved with all of Johnson's directorial efforts, ranging from an extremely brief cameo (The Brothers Bloom) to a starring role (Looper). Whenever a new Johnson film is announced, viewers are curious to see what kind of role Gordon-Levitt will take.
Johnson's critically acclaimed 2019 whodunnit Knives Out earned an Academy Award nomination for its screenplay, but it was also notable for its star-studded ensemble cast that read as a who's who of the Hollywood A-list. The upcoming Knives Out 2 is shaping up to be no different, but Gordon-Levitt is conspicuously absent from the principal cast in both movies. He still has a role in the Knives Out universe via a voiceover cameo as Detective Hardrock, who can be heard saying, "We have the nanny cam footage!" as Marta's sister watches a crime show early on in the film. This could be a springboard into a fun Knives Out 3 story.
Part of the appeal of the Knives Out franchise is that each entry tells its own standalone story, with Craig's Benoit Blanc working to solve a new case. This means Johnson can put him in virtually any situation every time out. It would be entertaining to see Blanc take a gig as a consultant on the show briefly heard in Knives Out, only for someone to be murdered on set during production. Blanc could then team up with Gordon-Levitt's "Detective Hardrock" (who is merely an actor playing a detective on TV) to crack the mystery.
This premise would allow Knives Out 3 to tackle buddy cop elements, giving Johnson an opportunity to put his trademark subversive spin on another classic industry genre. The original Knives Out saw Blanc work alongside Lieutenant Elliott and Trooper Wagner, so it wouldn't be out of the ordinary to see him play against another character interested in solving the case. The twist here, obviously, is instead of pairing with law enforcement professionals, Blanc would be stuck working with an amateur who may not know all the ins and outs of the job. There's potential for very humorous interactions between the two - whether "Hardrock" is actually more of an asset than Blanc initially believes or woefully in over his head as he deals with the seriousness of a "real" murder. Gordon-Levitt's range and comfort level with Johnson means he'd be a fit for anything the part calls for.
Another fun element of this Knives Out 3 story is the meta angle Johnson could explore, something he's demonstrated a knack for throughout his career. It'd be amusing to see him put his spin on detective show tropes, poking fun at long-established staples that are ripe for parody. Audiences would also be entertained by a narrative set within the entertainment industry, which is obviously something Johnson knows very well. It wouldn't necessarily be a movie about another movie or TV show in the traditional sense, but it'd be able to borrow from that playbook in places, giving viewers a peek behind the curtain. Of course, this isn't the only route for Knives Out 3 to go, but it has potential to be a wild ride.