Key Features & Upgrades:
Health & Fitness: Built-in heart rate sensors monitor, heart rate, and calories during workouts, working with Apple's Fitness app.
Improved Fit & Design: A revised ear tip design combining silicone and foam for better seal, plus a new extra-extra-small (XXS) size. The case is slightly smaller and features USB-C and MagSafe.
Sound & Performance: Offers 2x more Active Noise Cancellation (ANC) than the Pro 2, with improved Adaptive EQ for detailed sound, say this Amazon ZA review and this Digital Experience page.
Battery Life: Delivers up to 8 hours of listening time on a single charge with ANC enabled.
New Features: Includes "Live Translation," "Hearing Aid" functionality, and "Workout Buddy" features, reports this Apple SG page and this Apple LAE page