Halo 5: Guardians split-screen and LAN support detailed
There isn't any.
Earlier this week a fan of the Halo series contacted the Studio Head at 343 Industries, Josh Holmes, looking for clarification on whether split-screen had been removed from Halo 5: Guardians entirely. Holmes responded saying, "All multiplayer modes used full screen on dedicated servers, including co-op campaign, Arena, and Warzone."
The response from Holmes falls directly opposite of his previous statement from January, where he revealed that 343 Industries planned "to support 2-player split-screen for both multiplayer and campaign co-op."
An official statement from Microsoft has been released, split-screen will not be featured in Halo 5 and the game will not natively support LAN play. According to Microsoft split-screen would "compromise" gameplay:
"The decision [to remove all split-screen modes] was an extremely difficult one for the team, but one that was necessary to deliver the biggest Halo game to date. 343’s focus is to ensure that fans get the best Halo experience yet, and the team felt a split-screen experience would compromise the gameplay design and the visual bar they’ve set."
Removing split-screen is an interesting decision, Halo was an inclusive series -- it was a game that people could play in the presence of other individuals and have them join in and play; Couples could play the game together, roommates could play the game together, friends could play together. Bottom line, people played the game together and not always online in separate houses.