Riot Games has announced that a new game launcher will be released soon.

Riot Games wanted to create a client that would provide the best possible experience for its players when they first started playing. It appears that all Riot games have been using this multi-game client, which has been skinned for each game. Users will be able to discover and access all Riot titles more easily with the new client.
All Riot games on the desktop will be accessible through a single client, with each game having its product page. It should be noted that users can keep their single title shortcuts on their desktops if they so desire. Riot stated that each game will have its dedicated landing page with game-specific information and a dynamic call to action in terms of design. Game pages will also include cinematic backgrounds, event previews, and relevant news.
For those curious about the situation between Riot and Garena League of Legends, it has been confirmed that Garena users will not be able to play the upcoming client.
On September 20, the new Riot Games launcher will be available. Riot will begin rolling out the client globally on October 4 after a few weeks of testing and ensuring stability.
Source: Riot Games