According to the Beijing News, Bilibilli reportedly obtained the exclusive China-only broadcasting rights of the League of Legends World Championship for the price of 800 million yuan along three years ($113,349,768 USD, which is roughly $38M per year). This includes the next year's tournament that will happen in Shanghai, but also the two following competitions.
Bilibili is the Chinese equivalent of Youtube and was founded in 2009. Following their fast growth, they decided to expand to live streaming and flash games. Two years ago, they purchased the LPL team called IM and renamed it for Bilibili Gaming. The latter ranked fourth at the end of the 2019 season. Bilibili is also the owner of the Overwatch League team Hangzhou Spark.
Since Twitch is blocked in China, Bilibili seemingly had to compete with other domestic live broadcast platforms such as Kuaishou, Douyu, and Huya. It appears that the sell of the broadcasting rights took the form of an auction that Bilibili won thanks to their incredible bid.
Considering that China is reported to have over 100 million players for League of Legends only, these rights are certainly a good deal for Bilibili. We might even say that the price they paid to obtain the rights seems to be relatively low.
Bilibili didn't confirm this report nor made any announcement about the possible purchase of the rights.