What feature lets Halo: Campaign Evolved online co-op work across consoles and PC?

Cross-platform play lets Halo: Campaign Evolved online co-op work across consoles and PC.

The remake supports online campaign co-op for up to four players across Xbox Series X|S, PlayStation 5, and Windows PC. Players on different platforms can join the same session, while campaign progress can carry across platforms through linked accounts.

This is a notable expansion of the original Halo: Combat Evolved experience. The 2001 game supported local split-screen and system-link multiplayer, but it did not offer the modern cross-platform online campaign structure planned for Campaign Evolved. Halo 2 later helped popularize online Halo multiplayer through Xbox Live, but cross-platform co-op is a much newer feature.

A common mix-up is confusing cross-platform play with cross-progression. Cross-play means players on different systems can play together; cross-progression means campaign progress follows a player between supported platforms. Campaign Evolved is designed to support both, while console versions also offer two-player split-screen co-op.