Hello, there!
This is already simplified as there are no like terms that can be combined. x^3 is different than x^2, so it can't be combined.
x^3 is different from y^2 so it can't be combined.
And finally, x^2 is different from y^2, so it can't be combined either.
I hope I helped!
Let me know if you need anything else!
~ Zoe