The player touched the ball with the hand before shooting, according to the rules it is illegal.
It is funny how VAR works only against some teams.
The game before the goal was boring, in fact a couple of moments were for all 80 minutes, and then there was a real feast of soccer with goals, penalties and Giroud in goal and his save in the final minutes.
In general, Milan had a great match, you can see that the mood in the team is great, the players, even if not the most star players, but played and even Pulisic after Chelsea played so well.