During a rally on 6/20/18, at Duluth, Minnesota, Trump is spotted on multiple cameras making his usual entrance. Right as he enters, there is a supporter standing in front with a shirt with the letter Q. In less than a minute from Trump’s entry, he waves at the crowd and points directly at the man wearing the Q shirt, as seen in the video.
Other TV channels were also able to capture this moment.
From what is shown inside this video of a side-by-side comparison of the TV channel’s view versus the supporters view, it’s clear that Trump was giving a subtle yet very direct acknowledgement/confirmation of QAnon.