Would've been current events if I actually posted this back when it was new lol, but Raffaele Marciello (who's widely regarded to be one of the best sportscar racing drivers on the field right now) left Mercedes with the end of his contract last year. He's moved over to BMW, where's he's going to be driving their hypercar in WEC and part of their GTWC Europe squad in an M4.
Of course Lello's departure ended up getting overshadowed by an even bigger announcement - Lewis Hamilton's leaving Mercedes too after this season and going over to Ferrari.