There was that claim a few months ago that he has a clause in his contract saying he can manage Liverpool/Madrid/Bayern, and while I'm not sure if it's 100% true I do think he'll want to manage all of them at some stage, possibly even Sociedad too where he already done well with their B side.
The job could be a bit much for him straight after Klopp goes, but if it happened one day I really wouldn't be surprised, I think he'll carry on doing well. For me now though he should stay at Leverkusen for at least another season beyond this, probably more. Interesting to see how they do in the Champions League next season and most importantly if they win a league title. This season might be the chance but they still have the German cup and Europa League too.
I think if he was to go to Real Madrid first it might be beneficial for him/us down the line. They don't really hold onto managers and I think Ancelotti will be their first manager in probably decades to see more than three straight seasons in charge, bare in mind he is the record CL winning manager too. Maybe he goes to Madrid for a couple of seasons and they boot him, who knows. I know it's probably one of the most coveted jobs in the game too but surely there's less appeal in managing a Bayern side who win at least one trophy every season without fail. Liverpool is a proper challenge, if he wants one, and I think he will.