Even after the major twist at the end of Squid Game season 1, Gi-hun still doesn’t suspect that Player 001 is a plant in season 2 of the hit Netflix series. In Squid Game season 1, Gi-hun became close friends with Player 001 in the games, and was heartbroken when he was seemingly killed. However, at the end of season 1, Gi-hun learned that Player 001, whose real name was Il-nam, was actually one of the people who created the games. This was a major twist at the end of season 1, which changed how audiences viewed the entire season.

https://screenrant.com/squid-game-season-2-gi-hun-player-001-young-il-plant-suspicious-explainer/