Here's a little breakdown of the key features and updates the 2019 GMC Sierra 1500 received over time: 2019 REDESIGN INTRO - Off-road performance package (AT4 trim): this trim was introduced as an off-road-focused variant with standard 4WD a factory-installed 2-inch suspension lift and off-road-tuned Rancho shock absorbers. It also included skid plates hill descent control and a two-speed transfer case. - MultiPro tailgate: it offered six different configurations for easier access bed extension or even step-up assistance. - Duramax diesel option: in its debut it featured two engine options a 6.2L V8 (420 horsepower) and a 5.3L V8. Later models could also be equipped with a 3.0L Duramax inline-six turbo-diesel engine. - Traction select system: a selectable drive mode system was introduced offering drivers the ability to toggle between various driving models such as Sport Off-road and tow/haul. - CarbonPro bed: an innovative carbon-fiber composite bed material was available as an option offering greater strength and durability with lighter weight than steel. 2020 UPDATES - Trailer tech enhancements: advanced trailering features like 15 different camera views including a "transparent trailer" view were introduced. - Head-up display: a new available 15-inch diagonal display projected important information onto the windshield improving driver focus. 2021 UPDATES - Enhanced 3.0L Duramax diesel: this engine became more refined offering even better fuel economy and enhanced towing capacity making the AT4 more versatile. - MultiPro audio system: integrated Kicker audio system for tailgate parties was offered. 2022 UPDATES - Super cruise availability: it became available on the Sierra Denali tris and higher variants. though it wasn't initially available on the AT4 its introduction hinted at future tech capabilities across the entire lineup. - Interior overhaul: with a more premium look and better material choices.