Cut each cake into 8 slices. Combine cream cheese and powdered sugar in a bowl and beat at medium speed until smooth; set aside. To assemble the cake, spread half of the Cool Whip in the bottom of a 9" x 13" pan. Arrange 8 slices of cake on the whipped topping and press lightly. Spread cake with cream cheese mixture. Arrange remaining whipped topping. Spoon cherry pie filling over top. Chill 2 hours or until ready to serve.