Can the new 2019 16-inch Macbook Pro support 8K resolution? The Tech Specs site says the laptop simultaneously supports full native resolution on the built-in display and:

Up to two displays with 6016‑by‑3384 resolution at 60Hz at over a billion colors

Up to four displays with 4096‑by‑2304 resolution at 60Hz at over a billion colors

Since four 4K displays can be supported, I am assuming one 8K display can be supported. But I'm wondering if this can be done using one cable. The laptop supports two 6K displays, but this requires two cables, one for each display. Does this mean 8K resolution through one cable is impossible?
You cannot just assume that an 8K display can be supported just because it supports 4 x 4k displays - it doesn't work that way, I'm afraid.

As far as I know, no 8k monitors with a single cable solution exists today. That would require DisplayPort 2.0, which is coming with monitors next year. 

So yes, at the moment 8k resolution through one cable is impossible.