Nvidia briefly announced a few days that it had a macOS driver in the works that would support its latest 10-series graphics cards, and it appears the green team has made good on that promise. Driver release 378.05.05.05 is now available for macOS Sierra.
Despite the Pascal support, the driver release is somewhat of an odd duck, as driver updates tend to focus on updates for new hardware and performance improvements for newly-released software. However, since Nvidia cards haven't been inside Apple products for several years, all the hardware listed in the release notes is at least four years old. The driver updates are for Nvidia-equipped Mac Pro systems from 2010, 2009, and 2008. Additionally, Nvidia is offering beta support for select iMacs and MacBook Pro systems from 2013 and 2012.
Nvidia also doesn't call out Pascal graphics cards explicitly in the supported hardware list. Instead, the supported products page contains a brief list of the hardware originally sold in the Apple systems several years ago. The list is headlined by the venerable GeForce GTX 680 and Quadro K5000. Regardless, some Reddit users are reporting success with using this drivers with graphics cards like the recently-released Titan Xp, so it is the promised Pascal update.
Users with the right combination of Apple and Nvidia hardware can click over to Nvidia's site to download the driver release. There's a separate driver for those interested in making use of Nvidia's CUDA architecture. The rest of us might well wonder what's next for Nvidia and Apple. It's not unthinkable that the upcoming refresh of the Mac Pro might be equipped with an Nvidia graphics card.