Well, according to the show's creator, Hwang Dong-hyuk, it's certainly a possibility. As during a celebratory press conference held in Seoul for the series' multiple Emmy Award wins, Dong-hyuk said that:
“There will be no known Hollywood actor in Season 2. That’s not in the plan and if the stage changes, maybe in Season 3 – but for Season 2, it is still set in Korea. Leonardo DiCaprio did say he’s a big fan of ‘Squid Game,’ so maybe if time or chances allow, we can ask him to join the games.”
So, there you have it, and from the series creator no less. If the possibility presents itself, and if DiCaprio is free and willing to take part, we could very well be seeing him running the gauntlet of the game in Season 3.