ELI5: The US and China are not very good friends, but Chinese goods still get sold to US markets. China's gov't has a hand in every company in its borders, or so it is suspected, since this is routinely denied by the companies and the Chinese gov't. Some of those companies make computers that can watch and listen to us, whether we ask them to or not. The US is no longer comfortable with that arrangement.
Of course, it's a little more complex than that...
Of course, it's a little more complex than that...