https://www.gamespot.com/articles/at-the-last-minute-blizzard-strikes-overwatch-leag/1100-6455971/

In anticipation of the regular season of the first Overwatch League tournament on January 10, 2018, the Overwatch League and streaming video service Twitch announced a two-year media rights partnership providing global live access to the six-month competition. The first match goes live on January 10 at 4PM PST when the San Francisco Shock meet the Los Angeles Valiant. It can be viewed at overwatchleague.com through its embedded Twitch stream. Past matches will be archived under the site's Videos tab. You can also catch the matches directly on Twitch's website and at mlg.tv.

Twitch will be the exclusive worldwide third-party provider for all the Overwatch League matches with streams in English, Korean, and French. This exclusivity deal does not apply to China.