To me, he will probably leave after EURO 2021.
We have 3 rumors for now.
Manchester United, Juventus wants a swap with Pogba most wanted or Van De Beek.
First rumor, I think Juventus will get a better swap with Van de Beek, not with Pogba. Pogba is very selfish and is not good for Juventus in this period.
PSG, Juventus will probably ok with a swap with Icardi.
It will be a win win swap for all: PSG get a productive striker, Juventus get a younger, talented and already familiar with Serie A, Ronaldo would have a top club to win Champions League. Furthermore, he will join another national league: Premier League, La Liga, Serie A. Next would be Ligue I or Bundesliga.
and a rising rumor not under the radar yet... with Real Madrid.
Allegri wanted ISCO years ago... let see.
I think it will be one of these 3.
I don't think the last rumor will become true. It is the least possible rumor.