https://www.techradar.com/news/macs-finally-support-external-graphics-cards-with-macos-high-sierra-10134

External graphics card support, a feature promised by Apple since the launch of macOS High Sierra back in September 2017, has finally arrived via version update 10.13.4 that is available now.

Apple has detailed how the feature works through a support page on its website, noting that this function only works with Macs that support Thunderbolt 3 connectivity. So, that means MacBook Pro models released since 2016, iMac models since 2017 and the brand new iMac Pro.