If you have a Displayport display, you can use a displayport to mini displayport cable, use switchresx, should work good.
If it's HDMI only, as the sibling pointed out the HDMI port won't work. However, Startech makes a displayport to HDMI adapter which works ( https://www.amazon.com/DisplayPort-HDMI-Adapter-Converter-60... ) (just make sure you get one which supports 4k60hz, most DP -> HDMI adapters don't).
I'll consider this though I it would be probably be sitting unused after trying it anyway as I really have no need for it. Thank you for the information. Just to clarify, we're both talking about a late 2013 macbook pro retina? The other helpful commenter mentions the 2015.
Yeah, this is all on the late 2013 15" with the nvidia dgpu - https://support.apple.com/en-us/HT206587 has the official details on this BTW - they state that SST Displayport 3840 x 2160 displays are only supported at 60hz on the 15" from Mid 2014 on, but it actually works on the Late 2013 also with Switchresx.
If it's HDMI only, as the sibling pointed out the HDMI port won't work. However, Startech makes a displayport to HDMI adapter which works ( https://www.amazon.com/DisplayPort-HDMI-Adapter-Converter-60... ) (just make sure you get one which supports 4k60hz, most DP -> HDMI adapters don't).