The Packer is a two-door industrial truck built by MTL with a long series history spanning Vice City, San Andreas, GTA IV, GTA V and GTA Online, and it is due to appear in Grand Theft Auto VI. It has already been glimpsed in official material, appearing distantly during Lucia and Jason's Leonard County escape in the first trailer and driving through Port Gellhorn in the second.
Vehicle data via GTA Wiki (Fandom), CC BY-SA 3.0.