Will be interesting to read the arguments and hear what experts have to say.

There is some precedence that corporations do have first amendment rights.

A hypothetical argument from TikTok is they think they are allowed constitutional rights, in this case to publish whatever they want, in the act of doing a commercial activity and that the law which was passed to force a sale to a local owner is a violation of their right to speak freely.

I suspect TikTok operates in the USA under an American registered entity that is wholly owned by a foreign entity. Whether that grants or removes any such constitutional rights seems unclear.

Next, it doesn't seem like the law intends to block TikTok's "speech", rather it specifically allows the executive branch to block this particular type of foreign entity from doing business on American soil on the grounds of security, enforced most likely by blocking it from doing business with the app stores. This also has precedence - a lot of it, in fact - when it comes to security. The US blocks all kinds of foreign businesses from trading with American businesses. Like arms dealers and drug dealers.

So TikTok will need to defeat the idea that even as a foreign businesses they don't need to be subject to the whims of the executive branches power to block foreign businesses AND that even congress doesn't have the power to write a law that gives the executive branch this power (because, ya know, they just DID write that law).

And then TikTok will need to win on the idea that somehow their rights have been suppressed.

Seems like a long shot to me and the precedence that would be established by making it difficult for Congress to write laws that give the executive power to block foreign entities because it risks their unlikely right to speech in the US seems a bit whack.