your chain is dry, clean it, lube it.
your RD is dirty, clean it, lube it. Make sure the pulleys are clean roll easy and the upper pulley has a little side to side play.
your cassette is dirty, clean it.
your B-screw is screwed in to far, pulling the upper pulley to far away from cassette, adjust it.
if you pull you cable out or off, replace it, if not make sure tension is good.

if this has come gradually without any external reason (i.e. wreck), then it is usually a maintenance issue. RD