It's possible in the typical way of narration recording where in the timeline a video track and audio tracks play along with the recording which happens simultaneously into another track.

Hi, Steve!
Welcome to the forum!

It looks like you have missed a fundamental Article on "Vegas As Audio Workstation":
https://www.vegascreativesoftware.info/us/forum/article-recording-a-narration-in-vegas-pro--105357/

I understand the audio part but how about the video part? Like playing in a band? When I insert a video/audio track of a person playing an instrument and singing I'd like to ad another video/audio track of a person playing along with the first track. I'd like the 2 tracks to be independent of each other, video and audio. Is that possible?

Vegas does not record video in real-time.