Updated: Immobilize is not really a control like Fear, it is a condition which condition removal and condition duration reduction skills effect. So a Stun breaker or Stability won't do anything. But dodging or blocks will make an immobilisation attack miss or be blocked.
Two things to consider in GW2 stability and stun breakers. You need stability on to negate knock backs, knock downs, fears, stuns. Blinds are a condition
If you have been CC'd a Stun breaker will break that effect, remembering that Necros can chain fears with their wells and some skills. So in that case you need both.
The other aspect is condition removal, Fear is both a condition and a control spell. So condition removals and reduction in condition duration. Making whirl attacks and light field, with stability very powerful in negating a Necro's fears.