Nope, no button on mine for the windows. Though you can roll them down by holding unlock on the key fob. My '19 SLT didn't have the window button either, and it didn't have power running boards.
The buttons on my Denali (from left to right) are - Lane Keep Assist, Parking Sensors, Auto Start/Stop, Tailgate, Hazards, Traction Control, Bed Outlet, Hill Descent Control, and Power Running Boards).