Assuming a scientist actually said that, that would be fine. CNN doesn’t need to fact-check the scientists statement. Now, if evidence comes out that iPhones don’t cause cancer and CNN refuses to mention that there are refutations or disputes about that OR if CNN finds out affirmatively that those claims are false (the scientist admits they lied or retracts their statement) and doesn’t issue an on-air clarification or retraction (and if it was found that the scientist admitted to lying, that would almost certainly necessitate a retraction), CNN could be sued for defamation. That’s actually essentially what Dominion and others are doing with their lawsuits against Fox News and Newsmax and OANN.

You’re not wrong that there could be a damage done to the public figure/journalist's reputation. There could. But on the basis of New York Times vs Sullivan (a landmark Supreme Court decision and one of the most important first amendment cases), that doesn’t outweigh the free speech rights of the press. Moreover, the public figures by their nature, have more access and ability to respond to a defamatory claim, because they gave their own platform and reach. That’s why the standards of actual malice and reckless disregard are so high.

This is from a website with a very good definition of libel law (https://www.freedomforuminstitute.org/first-amendment-center...):

> The different standards exist because public figures are at the center of matters of public concern–matters that the press should report on as part of its “watchdog” role on the government. If journalists could be punished for every error published about a public figure, they might avoid reporting on controversial subjects that concern the public. The public would lose access to crucial information. > > Also, public figures generally have greater access to the media in order to counter defamatory statements, and to a certain extent seek out public acclaim and assume the risks of fame.