CUDA is an NVIDIA hardware toolkit. Many deep learning frameworks use it to accelerate training. Apple last offered an NVIDIA GPU in its MacBook Pro in 2014. A GeForce GT 750M, which provided a CUDA compute capability of 3.0.
At WWDC, Apple announced official support for external GPU enclosures in macOS High Sierra. This week NVIDIA followed suit.
“After skipping the assorted High Sierra betas, NVIDIA has rolled out drivers for its line of PCI-E graphics cards.”