Is there any chef who has 4 michelin stars?

It depends on how you think the stars are allocated.

Michelin always say that the stars are allocated to the restaurant, for the food it serves, and not specifically to the chef. The maximum number of stars that any restaurant can receive is three.

However, if a chef runs several restaurants (for example Joel Robuchon) then each of his restaurants can have a maximum of three stars, so it could be said that a chef has ten or fifteen stars, when all his restaurant stars are added together.