The Internet Archive’s captioning data tells us what the networks are talking about. Analysis of its footage by the Stanford Cable TV News Analyzer indicates how often each president (Obama, Trump and Biden) has appeared on the major networks.

On average since January 2021, Trump has appeared on MSNBC (in stills or video snippets) about 338 minutes per month, more than twice as often as he has appeared on CNN and Fox News (which has the lowest average). Biden has appeared on Fox News an average of more than 1,000 minutes per month, well above the 650 to 675 minutes he has been seen on CNN and MSNBC, respectively.

We can compare mentions of Biden on Fox News and of Trump on MSNBC to the same coverage on CNN. Since Biden took office, Fox News has on average mentioned him 1.9 times as often as CNN each month. MSNBC has mentioned Trump 1.6 times as often as CNN on average.