The latest mod for the game version you own allows you to open the game's main menu during dialogues and cutscenes. This mod is useful for players who want to open the main menu during the movies too.

Extract the content of the archive to the 'mods' folder of the Witcher 3 game. If you don't use a gamepad you could also add this line: IK_Pad_Back_Select=(Action=IngameMenu) (thanks to mainrouge for pointing this out).

It's a great mod that'll level up your gaming experience. So if you're looking for a tool that'll spice up your gameplay, try this mod now!