Modric has the potential to leave or retire and Kroos has the potential to extend his contract in the short term. This rumor spread when Madrid was reportedly very close to Mbappe, the arrival of the French player demanded changes in the scheme that had been formed by Ancelotti, it's true that Kroos will definitely consider playing regular minutes in the starting XI. Juventus came to take advantage of this condition, it is certain that the opportunity to recruit Kroos is very open, but all decisions are in Ancelotti hands, how much he can guarantee playing minutes for Kroos next season.
Juventus has lost its best midfielder like Pogba, that's why they are targeting players who are experienced and have been tested in all competitions. This season, Juventus is feeling the difficulty of competing with Inter Milan in the race for the Scudetto. It is hoped that Kroos presence will increase their chances next season and can help them compete in the Champions League next season. On the other hand, a player like Kroos will not lack interest, especially since he can be recruited on a free transfer, Juventus will have to compete to get his signature.
The arrival of Kylian Mbappe if we're getting this well shouldn't affect the role of Luka Modric in the future. Kylian Mbappe arrival would only affect these fellow attacking lads and not the midfielder's. In between they really both two different players and would never have a shared business in that role.
Real Madrid may likely let Luka Modric leave, not because he's lacked energy, vision and creativity. But, I feel like it's time to see him leaving the club after all these years. He's more likely to leave than anyone amongst or between him and Toni Kroos.
Juventus now wants him. Saudi Arabian League also. I think the move to the Old Ladies would ne much preferable.