Halo Online

About

Halo Online was a free-to-play multiplayer-only Halo game that was tested exclusively in Russia.

The game was cancelled on August 24, 2016, when the developer, Saber Interactive, announced that "the current form of Halo Online will not be released." The reason they gave for the cancellation was that Microsoft had "failed to [make] decisions on the future of the project."

Source: IGDB