The current presidential limo is a 2018 Cadillac. The doors are eight inches thick, armour-plated, and weigh as much as the door on a Boeing 757. When the doors are closed, it provides an airtight seal in the event of a chemical attack.
The windows on the side, in the rear, closest to the president are bullet proof and 5 inches thick, and the steel undercarriage is bomb proof.
The fuel tank is also armour-plated and a special foam product is used in addition to the gas that would prevent it from exploding even after a hard direct hit.