Searched the forums and didn't see any posts about this yet. So to save people the time that I wasted trying to figure out why after the April 2018 update your real tone cable isn't working.
With the April 2018 update they added new privacy features that block most apps from using your microphone.
So to get it to work again go to your windows settings and search microphone privacy and switch it to allow apps to use your mic. I wasted an hour trying to figure it out and reinstalled Rocksmith all over again when all I had to do was click this setting. Hope this saves some people time after they get the windows update.