Pro Tools (including the free "First" tier) natively supports the HUI (Human User Interface) protocol. The HUI protocol was originally co-developed by Mackie and Digidesign (Avid’s predecessor). Consequently, Mackie controllers can switch into "HUI mode" to communicate perfectly with Pro Tools.
Disclaimer: This article reflects the current status of Avid products as of 2025. Avid Technology has discontinued Pro Tools | First and no longer hosts support pages for that specific software iteration. avid.com pro-tools-first-mackie