Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9x13-inch baking pan.

Combine cake mix, eggs, and apple pie filling together in a large bowl. Pour into the prepared pan.

Combine brown sugar, flour, butter, cinnamon and walnuts. Sprinkle over the top of the cake batter.

Bake in the preheated oven until a toothpick inserted into the center of the cake comes out clean, about 35 to 40 minutes. Allow to cool.