Krauthammer had a malignant tumor removed from his abdomen in August and experienced a series of setbacks in his treatment.
"I think you all know I'm an honest person who works extremely hard to provide you with accurate information at all times," Sanders said.
Bill Kristol slammed the Fox News host, saying "one of the most gifted" young reporters was overseeing a show that is "close now to racism."
Press was blocked from covering an event in Asia where Trump and Putin may—or may not—have discussed Russian meddling in the 2016 election.
A report finds that "liberal media" may not be as biased as President Donald Trump thinks it is.