In the just-concluded Club World Cup tournament, Chelsea showed that PSG could be beaten, but the defeat will not have any negative impact on PSG's performance next season, and I believe PSG is still a big threat for clubs in the UEFA Champions League because there are a lot of big clubs that are still trying to strengthen their teams to be at the level of the PSG team.
Losing is part of the game. PSG losing to Chelsea in the final of the Club world cup doesn’t make them not champions. PSG have dominated the French league and Europe last season so losing one game to Chelsea does not take away their championship title or reputation from them.