The Halo Infinite cooperatively campaign was announced at the end of the last year in the Winter Update. Co-op campaign allows you and your friends to play the Halo Infinite Campaign together. This mode can be played with a maximum of four players.
Halo Infinite co-op can be played on PC, Xbox One, Xbox Series S/X and cross-platform. In that way, if you are a PC player you’ll be able to play with your console friends.
In the article published by Halo Support, the game explained step by step how to play the co-op campaign:
- Launch Halo Infinite.
- Select the "+" symbol underneath your Nameplate to add players to your Fireteam.
- From the Social menu, select the Friends tab.
- From here you can join a friend's Fireteam or invite them to join yours by selecting their Gamertag and choosing from the options on their Profile menu.
- Once the Fireteam has been formed, the Fireteam Leader (FTL) should navigate to the Campaign menu in the Play tab. The FTL is identified by a crown icon in the Fireteam widget located in the bottom left of the screen and in the Social
- In the Campaign menu, the FTL can select to Continue their latest save file, start a new save file, or load a specific save file.
- Once the FTL selects their save file, they will enter the Campaign Co-Op menu where they can select the preferred Difficulty level and which Skulls to enable.
- After pressing the Start Co-Op button, the rest of the Fireteam will be prompted to select their save file.
- The FTL can select Start Game to initiate the session once all players select their save file.
Unfortunately, the split screen co-op was canceled, 343 Industries announced last year. This mode would allow you and your teammates to divide the screen and play together. However, it’s possible to play the co-op in Split-screen using a glitch in the menu, allowing you to add a maximum number of three players in the campaign. This glitch can only be made in Xbox Series S and Xbox Series X.
Here is a tutorial from @HaloCreation and @Zeny_IC.