Halo 5: Guardians will NOT support split screen in campaign and multiplayer. At first Halo 5 was going to support 2 player split screen but now Josh Holmes from 343 industries has now confirmed on Twitter it will not feature any split screen.
Halo 5: Guardians will only support full screen play across all modes including Warzone, Arena and Co-Op Campaign meaning that only one player will be able to play, per console. This will be the first ever Halo game to not support split screen.
Thanks to our friends at Beyond for the info.
Stay tuned for more Halo 5 info!