Robert Lewandowski is of course one of the greatest strikers now. He is getting older but his performance improves more in time. I think that he is better than last season now for example. He can break a new goal record in the Bundesliga if he goes on like that. Bayern Munich are really lucky to have him but he seems likely to leave this summer also I think. Actually it will depend on the offers for him. If he gets a really satisfying offer from another big club, then maybe he would make a change in his life from now on.
Bayern is trying to renew Lewandowski contract and I don't think he wants to leave the club. He is doing fine there, a change will not make him better but may end his career. AFAIK PSG is interested in his services which might be interesting especially if Mbappe will leave the club and since Messi isn't top right now.
Bayern's great success in recent years has certainly been due to Lewy's contributions, and I don't see any reason for Bayern not to extend Lewy's contract this summer. There are some risk that Lewandowski would be tempted by other offers and that Bayern could even lose him, but it would be a huge mistake for them to let their leading scorer go. Having said that, if Lewy had really wanted to move to Real Madrid, it would already have happened. Honestly, I don't even see Lewy wanting to go anywhere and I hope Bayern and Lewy are able to extend their union even longer than two years.