No, they’ll just shut off his mic.
I believe broadcast networks have a 7 second delay to cut off the volume if needed (example: when Conner McDavid won the Con Smythe winner for the 2024 NHL postseason, ABC cut off the audio feed for several seconds because the Florida Panthers fans were upset and likely were hurling expletives that were picked up by the microphones). However as long as Trump doesn’t use expletives, I don’t see why the audio will be blocked since it would be Trump’s turn to speak. CNN shouldn’t block both Biden and Trump at the same time.