Do enemies respawn indefinitely in target escort missions?
Solution 1:
There are a finite number of enemies.
The Target Extraction missions always end with the objective, "eliminate any remaining hostiles," unless you've already killed them all.
You can also move your squad into the extraction zone after the VIP and end the mission that way. However, you won't get your loot and any XCOM personnel outside the zone when you end the mission are lost.
XCOM wiki