Preheat the oven to 325 degrees F (165 degrees C). Grease and flour a 10-inch Bundt pan.

Stir cake mix and sugar together in a large bowl. Make a well in the center; add eggs, cream cheese, oil, and vanilla. Beat on low speed until blended. Scrape down the sides of the bowl; beat on medium speed for 4 minutes. Stir in blueberries. Pour batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center of the cake comes out clean, about 40 to 45 minutes. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.