With Real Madrid winning the most recent UEFA Champions League campaign, they automatically qualify for the 2024–2025 FIFA Club World Cup.
Real Madrid to opt out of FIFA Club World Cup

However, Carlo Ancelotti has disclosed that the Spanish giants plan to turn down an offer to participate in the upcoming tournament.
The old format involved seven teams competing for the trophy over a period of about two weeks. Winners of the AFC Champions League, CONCACAF Champions League, Copa Libertadores, OFC Champions League played against each other in a single knockout match. The winners in these three games will then advance to the semifinal stage, where the UEFA Champions League winner joins them to complete four teams.
With the newly introduced format, the FIFA Club World Cup is scheduled to grow to 32 teams and take place in the US over the course of four weeks the following summer. The new format also came with a different requirement for participation, which involves recent continental successes and UEFA rankings.
After winning the competition five times in the previous nine years, Madrid is expected to be among the top teams to compete.
What Ancelotti said

However, Ancelotti is convinced that his team would not participate since FIFA has not offered them enough money, and he believes that other teams will do the same.
”FIFA forgets that the clubs and players will not participate in that tournament,” Ancelotti said in an interview with Il Giornale, as reported by Daily Mail.
”A single Real Madrid match is worth €20m (£17m) and they want to give us that money for the entire competition. Negative.
”Real Madrid, like other clubs, we will decline the invitation,” he added.
FIFA Club World Cup revolt

FIFA’s intention to extend the Club World Cup has come under fire in recent weeks due to worries over player welfare.
PFA president Maheta Molango even threatened to sue FIFA if the organization didn’t back down from its intentions to grow the Club World Cup.
Manchester City CEO Ferran Soriano is also of the opinion that the move to a 32-team format would contribute to the already existing crisis of fixture scheduling, suggesting that the Premier League Champions may also think twice about participating.