Faint humming sound when clutch is engaged

At an idle, when I push in the clutch, it makes a faint humming or wining sound. It definitely wasn't there before. I've owned this truck for 6 years. What could be the issue? I have a 2013 Tacoma V6 4x4 TRD Sport 6-speed manual with 143,000 miles. I have not done anything crazy and no off-roading (unfortunately) in several months. Just normal highway driving.

 

Most likely throw out bearing, usually it’s the other way around tho when you push the clutch the sound goes away so not 100 percent. Those trans snouts/input shaft were the bearing rides wears out due to poor metal choice, and other factors witch is explained in the product details . They have a upgrade that eliminates the problem https://urdusa.com/throwout-bearing-upgraderepair-kit-2005-tacoma-v6-6-speed/