Github CLI? Hub? って思ったけど、このへんに書いてあった。
https://github.com/cli/cli/blob/master/README.md#comparison-with-hub

> Comparison with hub

For many years, hub was the unofficial GitHub CLI tool. gh is a new project for us to explore what an official GitHub CLI tool can look like with a fundamentally different design. While both tools bring GitHub to the terminal, hub behaves as a proxy to git and gh is a standalone tool.