If you are going from a 7" display to 8", you'd need the display, module, and have it programmed for your truck through the dealer or WAMS. Oh, and add the SD card reader in the center console. Do you have an IOR, IOS, or IOT?
IOR Audio system, 7" diagonal GMC Infotainment System, includes multi-touch display, AM/FM stereo, includes Bluetooth streaming audio for music and most phones; featuring Android Auto and Apple CarPlay capability for compatible phones
IOS Audio system, 8" diagonal GMC Infotainment System, includes multi-touch display, AM/FM/SiriusXM stereo, Bluetooth streaming audio for music and most phones, Android Auto and Apple CarPlay capability for compatible phones, advanced voice recognition, in-vehicle apps, personalized profiles for infotainment and vehicle settings
IOT Audio system, 8" diagonal GMC Infotainment System with Navigation, includes multi-touch display, AM/FM/SiriusXM stereo, Bluetooth streaming audio for music and most phones, Android Auto and Apple CarPlay capability for compatible phones, advanced voice recognition, in-vehicle apps, personalized profiles for infotainment and vehicle settings. Includes greater memory.
Any upgrade will not be cheap
https://www.whiteautoandmedia.com/product/silverado-sierra-wireless-car-play-android-auto-navigation-and-hd-radio-upgrade/