First drive: 2020 GMC Sierra 3500 Denali eclipses its former self

Until the GMC Hummer EV makes its debut in the fall, the 2020 GMC Sierra Denali Heavy Duty pickup truck totes the truckmaker’s banner as a flagship. It’s suited to the task. Up to three tons of anything can be heaved into its boxy rear bed, or it can tow up to 15 tons—roughly equivalent to the weighty expectations ahead for...