Specific co-op details haven't been shared at this time, but it does appear four player co-op is supported similar to the original Crew
The newest iteration in the revolutionary franchise, The Crew 2 captures the thrill of the American motorsports spirit in one of the most exhilarating open worlds ever created. Welcome to Motornation, a huge, varied, action-packed, and beautiful playground built for motorsports throughout the entire US of A. Enjoy unrestrained exploration on ground, sea, and sky. From coast to coast, street and pro racers, off-road explorers, and freestylers gather and compete in all kinds of disciplines. Join them in high-octane contests and share every glorious moment with the world.