Skull and Bones does not offer split-screen gameplay on Xbox Series X or any other platform. This means you cannot play the game cooperatively with another player on the same console using separate controllers.
Here’s a confirmation:
While the lack of split-screen might be disappointing for some players who prefer local co-op experiences, Skull and Bones focuses on online co-op, allowing you to connect and play with friends regardless of their location or platform. This can expand your potential pool of co-op partners and offer a more diverse social experience compared to local co-op.