Big changes are anticipated at Old Trafford in the offseason as new boss Erik ten Hag replaces Rangnick, who is taking on a dual role as United consultant and Austria coach.
Nemanja Matic, Juan Mata and Edinson Cavani all made their final home appearances as United players in Tuesday's (AEST) 3-0 defeat of Brentford.
And there has also been widespread speculation around Ronaldo and how he will fare under Ten Hag – or whether he could even move on a year after his return to the club.
But Ronaldo has scored 18 goals in just 29 Premier League games this season, and Rangnick does not foresee United's number seven leaving.
Rangnick said of Ronaldo's response to the crowd at full-time: "I don't think why it should be a wave of goodbye.
"He has another year of contract, and as far as I know, he will be here next season again."
Meanwhile, Ronaldo posted on his Instagram page: "Once again, great support from the stands.
"Let's take this opportunity of our last game of the season at Old Trafford to thank our amazing supporters, who endured a difficult season by our side and never abandoned us.
"Thanks, guys. Your support means the world to us and our goal is to become better everyday, so that we can achieve what we all want: glory for Man. United!"
Along with veterans Matic, Mata and Cavani, Paul Pogba and Jesse Lingard are set to depart United, while Aaron Wan-Bissaka has been linked with a return to Crystal Palace.