To be honest I had kind of assumed 60 Hz hums were a thing of the past using HDMI connections, but maybe I've just been lucky. As I recall, a common first suggested step was to make sure all devices were connected to the same outlet, and preferably even a single power strip.
If the TV happens to be connected to a coax cable (cable TV/antenna) try removing that and see if anything changes. (These connections may give the TV a different ground.)
I would also suggest browsing 60Hz threads in general AV forums since I don’t recall seeing one on this forum before.