actually, the correct spelling is wassup joe, not what's up joe?. The term means how are you not hi, or hello. It did not come from what's up yo. It came from the last 20 years of urban people using the name joe as a term of endearment; the same way you would use, what's up buddy.
Originating from a viral video of a black man named joe shouting "Joe me up" with his fist in the air, joe me up is a parody of dab me up, a semi-popular meme that had originated in discord.
A term used regularly by Jack Williams of Granville NY. The term is widely believed to have originated with Mr Williams and was applied to situations Jack did not approve of.