Update: Halo Studios says it made a mistake and accidentally posted incorrect information about playing Halo: Campaign Evolved's PS5 version in split-screen co-op. You don't need two active PlayStation Plus memberships, just two PlayStation accounts and linked Microsoft accounts.
"We incorrectly stated that PlayStation Plus is required for local co-op splitscreen play. Local splitscreen co-op requires a PlayStation account for each player but does not require a PlayStation Plus account," the studio tweets. PSN memberships are required for online co-op, as is the norm.
