CD Projekt Red did not say anything about the trip or whether it will affect the release of Cyberpunk 2077 somehow, but they would probably say something if the game is set to face a long delay. More than likely they will continue to work behind the scenes and will run it when it's ready.
Regarding the place where Stepien will best serve Blizzard, it's really up to now. Most of their games benefit from storyline stories; and there is a great chance he just contributes to a similar Diablo 4 or some unannounced project to the company. This will certainly benefit from his experience, that's for sure.
We'll see if CD Projekt Red has anything to say about the departure in the coming days. Cyberpunk 2077 does not currently have exit date but is set to arrive for Xbox One, PlayStation 4 and PC when it's done
What do you think of this change in employment? Sound on Twitter by reaching @TheDCD!