Kevin Costner desperately wanted to direct Clint Eastwood's most acclaimed Western, which overshadowed their eventual movie collaboration. The careers of Clint Eastwood and Kevin Costner have interesting parallels, with the two having their movie breakthroughs thanks to a Western. Eastwood had the groundbreaking Dollars movie trilogy, while Costner stole the show in 1985's Silverado. Eastwood later used his star power to move into directing too, which is something Costner would do also, beginning with the acclaimed Dances with Wolves.

https://screenrant.com/unforgiven-movie-kevin-costner-director-clint-eastwood-perfect-world/