What percentage of my portfolio should be cash?

Other than holding on to a bit of extra cash for spending/emergency funds, should I be holding any additional cash right now? Or should I be dollar-cost averaging all of it into index funds/my roboadvisor?

I just did a post about this!

https://www.instagram.com/p/CGvKngenXaN/

Wow what timing! And from the man himself no less.