Use an external display with your iMac Pro
The Thunderbolt 3 (USB-C) ports on your iMac Pro support video output. You can use an external display, a projector, or an HDTV with your iMac Pro.
Note: The Thunderbolt 3 ports on your iMac Pro are managed by two controllers, one for the two left ports, the other for the two right ports. Each controller can support two 4K displays or one 5K display. So you can connect up to four 4K displays or two 5K displays to your iMac Pro. To connect two 5K external displays, for example, connect the first 5K display to either of the first two Thunderbolt 3 ports, and the second 5K display to either of the last two Thunderbolt 3 ports.
To connect this device to a Thunderbolt 3 (USB-C) port
Use this cable or adapter
Thunderbolt 3 (USB-C) display
Thunderbolt 3 (USB-C) cable
USB-C (USB 3.1) cable
Thunderbolt 2 display
Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter
HDMI display or HDTV
USB-C to HDMI adapter or a USB-C Digital AV Multiport adapter
VGA display or projector
USB-C VGA Multiport adapter
DisplayPort or Mini DisplayPort display
USB-C to DisplayPort or Mini DisplayPort adapter
DVI display or projector
USB-C to DVI adapter
If you have an HDTV connected to an Apple TV, you can use AirPlay to mirror your iMac Pro screen in up to 1080p HD. See Use AirPlay on your Mac for details.
Adapters and other accessories are sold separately. Visit apple.com, your local Apple Store, or other resellers for more information and availability. Review the documentation or check with the manufacturer to make sure you choose the right product.