I've also heard about the rumours regarding Cristiano Ronaldo to join Bayern Munich in this summer. However, I don't expect this to be more than a rumour in the coming days. Because I'm feeling like Ronaldo will decide to stay and play for Manchester United one more season. For Bayern Munich, it would be nice to bring Ronaldo to Lewandowski's place I guess. Their priority now is to keep Lewandowski of course. They have signed Mane also but I don't know if they are thinking him for that position in that situation.
I think it will be difficult for Manchester United to allow a talented striker to leave the team at this moment where Manchester United got a new manager. Cristiano Ronaldo has many strategies to demonstrate in next season to make Manchester United fans happy because this season performance was very poor for their like which next season will be more better than this season. I think Bayern Munich will allow Lewandowski to finish next season since they have signed in mane the formal Liverpool striker which will really help the team to perform well in next season.