A lot of times music will mesh, or glue, together so well that it's hard to really hear all the different parts going on in the song, or each instrument by itself.
If the song is in stereo, there’s a really good chance the guitar part you’re trying to learn is panned over to one side of the speakers.
One great way to try “cutting out” some of those other instruments and let the one you want to learn be soloed, is to do something called "hard pan" the speakers. This basically means to silence one of the speakers, so that only one speaker is playing at a time.
This doesn’t always work, but sometimes the song has been mixed in a way where the instrument you’re trying to learn is 100% only in one speaker. By cutting out the opposite speaker, you can essentially mute a lot of the other tracks, or at least make them quieter.
This can also be a really good way to take a song apart and learn more about how it was put together.