Please be aware that for co-op squads wanting to access DLC content, both players must own the DLC. If only one person owns the DLC, you won't be able to access that DLC-specific location. In addition, once a save has interacted with DLC content, it won't allow a non-DLC owning teammate to join that save at any point afterward. For that reason we recommend keeping multiple save files before and after any DLC locations have been visited.