while obviously nobody is planning to have dogfights, one can imagine 2 stealth fighters that no missile can lock onto while pilots can actually see each others planes - times for good old school dogfight :)

(the probably exception for missiles is IR missiles - as long as you can get behind the enemy plane it would probably be able to lock onto it, even on the stealth one, and trying to get behind each other means pretty much dogfight again. Or similarly, say regular missile can lock onto a stealth plane only from much closer distance - from behind would be much more preferable position as stealth planes are less stealthier from that direction and at close distance the target plane has much less chances to shake off the incoming from behind missile)