*Update September 9th, 2016:
Halo 5: Forge, the extensive level editor for the Halo universe is now live. Microsoft and 343 Industries released the powerful tool the day before yesterday already, so one day before its scheduled release. Players can now build and try out their very own levels and mods for Halo 5 on their PCs.
Original news from August 29th, 2016:
The experiment that was Halo Online has officially failed. Microsoft is not going to release the free-to-play version of the shooter franchise in Russia anymore. The online game has never made it out of its beta status. Microsoft, 343 Industries, and the two development partners Innova Systems and Saber Interactive have officially scrapped the project. Microsoft was hoping for a similar success to Activision’s Call of Duty Online in China. Activision had successfully adapted their iconic CoD franchise to the Chinese market in terms of gameplay and monetization. Microsoft has unfortunately failed to achieve similar success in Russia.
Instead, PC players will have to make due with Halo 5 – Forge which was announced by Microsoft and 343 Industries in May. The level editor called Halo 5: Forge is going to be released for Windows 10 PCs on September 8th. Players can use the online game to create maps and try them out for free, even if they don’t own Halo 5 for Xbox One. It will also feature the possibility to create custom games that up to 16 players can participate in.
The only precondition to play this toned down multiplayer version of Halo 5 is a Windows 10 PC, since the online game will only be available in the Windows 10 Store.
Source: Gamasutra, Official press release