The "Protecting Americans from Foreign Adversary Controlled Applications Act" would ban TikTok in the US, unless it is sold to a non-Chinese owner.  It passed the House 352-to-65. 
The Senate Leader hasn't decided when the bill will make it to the floor for a vote. There are concerns over free speech restrictions and presidential overreach. 
The driving factor according to the White House: Chinese ownership of ByteDance poses grave national security risks to the United States, including the ability to meddle in elections. It's particularly concerned that the Chinese government could meddle in the algorithm that serves up content. 
Financial Analysts are concerned it could prompt China to retaliate against American's firms' business activities in China. Disney has a theme park, Tesla gets almost of a quarter of its revenue from China, about half of Amazon's third-party partners are from China. But remember, Platforms like Facebook and YouTube are blocked in China. 
TikTok is not going down without a fight. It has called on its 170 million US users to phone and write to their representatives. 
In 2020 the company created a deal with Oracle to separate US user data from the rest of the world, and host that in the US. Arguing this is a breach of the first amendment is likely to be the company takes its lobbying.