https://www.cnet.com/news/trump-campaign-wants-answers-on-facebook-and-twitter-political-bias/

The Trump campaign and the Republican National Committee sent a letter to Facebook's Mark Zuckerberg and Twitter's Jack Dorsey with complaints about how the social networks treat conservatives. 

Brad Parscale, Donald Trump's campaign manager for the US election in 2020, posted the letter to Twitter on Thursday, where it received hundreds of retweets within minutes. The letter requested information about Facebook and Twitter's efforts to "prevent political bias" on their social networks.