Ancelotti worked with Ronaldo as Real coach and when he was sacked, the decision upset this year's Ballon d'Or winner.
"Ancelotti as coach, he can train where he wants, whenever he wants, he is an incredible person, as well as a great coach, he won everything, I hope to work with him one day," Ronaldo told Mediaset.
"Italy will not change anything but I think it deserves to be in the World Cup, it always deserves it. It's a surprise that they're out."
On beating Juventus in the Champions League final last season, Ronaldo added: "The Cardiff final we played was great, changing our attitude and winning the game. It was a challenge to win this trophy."