Fig has teamed up with Harmonix to bring Rock Band 4 PC to market as long as they can reach their $1,500,000 goal.
The PC version of Rock Band 4 was already in planning, scheduling, scoping and preparation after the game released on console, the funding being requested allows Harmonix to take game the rest of the way and get it released.
The version that is being targeted is for Windows, there are no plans for Mac, Linux or SteamOS versions according to the campaign FAQ.
If you want to back Rock Band 4 PC you can pledge to obtain shares which will allow you to profit from Rock Band 4 PC sales or the more traditional rewards structure on the Official Campaign page.
Rock Band 4 is currently available on PlayStation 4 and Xbox One.