Preheat oven to 350 degrees. Lightly spray a 9x13 pan with baking spray, set aside.
In a mixing bowl with an electric mixer, mix cake mix, pumpkin, water, eggs and oil until smooth. Pour batter into prepared pan and bake in pre-heated oven for 28-33 minutes or until tooth pick comes out clean when inserted
As soon as the cake comes out of the oven, while it is still hot, poke holes into the cake with the end of a wooden spoon. In a microwave safe bowl, heat up a ¾ cup of the caramel sauce for about 20-30 seconds, just to warm (making it easier to pour over the cake). Pour the warm caramel sauce over the top of the hot cake, making sure to get the majority of the sauce into the holes of the cake. Let the cake cool completely.
Once the cake is cool, prepare the cream cheese frosting. With a hand or stand mixer, cream together the cream cheese, powdered sugar and milk until smooth and creamy. Add the whipped topping, and fold into the cream cheese mixture. Spread the frosting over the top of the cake, gently pressing the frosting into the holes of the cake. Smooth out evenly.
Drizzle the top of the cake with the remaining ¼ cup of caramel sauce. For a decorative effect, drag a toothpick through the opposite lines of the caramel sauce in the opposite direction to make a herringbone design. Refrigerate any leftovers. Enjoy!