Answer:
The didn't immigrate to Palestine at the first place.
Step-by-step explanation:
After the destroying of Jerusalem at the 70th century many Israelites immigrated to many places to earth especially to Africa and Europe. Like Ethiopia (Tribe of Dan) and Zimbabwe (Tribe of Levi) in Africa and also to Europe like Germany.
Israel and Palestine are neighboring countries even though there is no peace between them (we can see that through history), so even if they migrate to Palestine they won't be welcomed.