The TikTok app is served by the US data center operated by a team in the US. If they violate any US law, federal regulators can find out and punish TikTok based on evidence like how they fined Facebook. Being owned by the CCP doesn't mean that they cannot obey US law. And it is really hard to imagine how CCP can harm the interests of the US people with those short fun videos. Does Trump believe virus spreads via these short videos?