Line an 8-inch square pan with waxed paper; set aside.
Spoon peanut butter and cream cheese frosting into a microwave-safe bowl; heat in the microwave on high for 30 seconds. Stir mixture and heat again for 30 seconds; stir again until thoroughly blended.
Pour mixture into the prepared baking pan. Refrigerate until chilled, about 1 hour before cutting into bite-sized squares.