You like to keep all your Drupal website code in Github (GUIs for PRs! Clear code diffs! Searchability! Visibility within your organization!), but hosting partners like Pantheon and Acquia have their own Git repositories that tie into their deployment processes. This session will walk you through taking an existing Github Drupal repository and automatically deploying any updates to that repository's main branch (eg, by merging in a pull request) to a Pantheon dev environment.
(As of August 2023) Github accounts include 2000 minutes of Github actions execution minutes for private repositories, and Pantheon's Silver plan is also free. So if you'd like to reproduce what I'm showing to explore the possibilities for your own websites, you can do so at no cost.