Want a boxer dog but would a part boxer dog be better?

up to boxer dogs 4 and 5 but both getting old now 12 and 10 got them both from pound, but both got health issues now and not much vet can do about it. last pure breed boxer i had only made it to 7 years before vet had to put him to sleep. at least a part boxer would have a better immune system. what kind of boxer-cross keeps the same traits etc playful, nosey, friendly,