Preheat oven to 350°F (175°C) and grease a 9x13 inch baking pan.
Prepare the chocolate cake mix according to the package instructions and pour the batter into the prepared pan.
In a medium bowl, beat the softened cream cheese and creamy peanut butter together until smooth.
Add the melted butter and powdered sugar to the cream cheese mixture, beating until well combined.
Drop dollops of the peanut butter cream cheese mixture over the surface of the raw cake batter.
Sprinkle chopped Reese's Peanut Butter Cups, chocolate chips, and peanut butter chips evenly over the top.
Use a knife to gently swirl the toppings and cream cheese mixture into the cake batter.
Bake for 40 to 45 minutes until the cake is set but the cream cheese pockets remain soft.
Remove from oven and let cool slightly before serving directly from the pan.