US President Donald Trump says he plans to ban the Chinese-owned video app TikTok. US officials are currently looking into the possibility that China can access user data collected by the app. An outright ban would come as a blow to TikTok's millions of fans, but its exploding popularity has also raised red flags. The plan comes on the heels of tit-for-tat consulate closures in Houston and Chengdu. Is TikTok a threat to US national security?