Squid Game season 1’s ending definitely left the door open for a sequel, although many wondered if the setup would be vastly different and not focus as much on the actual game.
Sole surviving protagonist Gi-hun seemingly opts to try and take down the organization behind Squid Game rather than move on with his daughter, and it’s unlikely he would willingly participate in the game again, even if baited by Squid Game’s resident recruiter.
However, there’s always a way for dystopian organizations like this to force compliance, so perhaps Gi-hun’s daughter will be used to bait him back into the game. Squid Game’s complex in-universe creator Il-nam is also apparently dead, which may lead to an even less fair game than before. Since the Squid Game season 2 plot will also see the return of Jun-Ho to the cast, it could be that he survived his brother’s bullet and that the Front Man’s intention was never to 𝓀𝒾𝓁𝓁 his brother, but rather, to save him.