To hear my friend on the stream?

I want to stream Fortnite with my friend over OBS. I've tried it but you can't hear my friend. We're talking about the Fortnite voice chat. How do you hear him.

If you hear the game sound in the stream, you should also hear your friend because the in-game chat is part of the game sound.

Is there an option in the game settings to block voice chat as a second audio source for recordings?