Earpieces. At this point most dumb candidates and puppet leaders wear them.
He was waiting to be told what to say.
Watch his eyes drop down and his expressions. He’s listening to his staff argue about how to respond.
https://www.dailymail.co.uk/news/article-8381227/Trumps-actions-render-Trudeau-speechless-21-seconds.html
https://www.salon.com/2016/09/09/the-phantom-earpiece-phenomenon-why-presidential-candidates-are-consistently-accused-of-cheating-during-debates/
https://www.washingtonpost.com/news/the-fix/wp/2016/09/08/hillary-clinton-earpiece-speculation-conjures-the-ghost-of-george-w-bushs-back-bulge/