The confirmation came directly from official game blog, where it was announced that if a party leader is in possession of one of the paid DLCs, all his companions will have the opportunity to play the content. This includes maps, gameplay elements and any campaigns.
"No separation, no exclusion, no division"
Back 4 Blood is a zombie-themed cooperative first person shooter that aims to be the spiritual heir of Left 4 Dead and will trace a good part of the structure and mechanics. At E3, in addition to the confirmation of the presence of a PvP mode named “The Swarm”, it was announced that the game will be available on Xbox Game Pass from the launch date, set for 12 October.