Egypt took Gaza in the '48 war, built camps and put Palestinians (then called Arabs, the word “Palestinian” still most often referred to Jews) in them. Nobody much cared until Israel took the territory in the Six Day War and Egypt refused to take it back after.
Likewise Jordan annexed West Bank, built its camps, put Palestinians in them and held it until '67. Lebanon, Syria, Jordan and Egypt all built camps for Palestinians WITHIN their own borders and refused to assimilate them or allow them to become citizens. They used Palestinians as pawns in their quest to eliminate the infidel state. It didn’t work. No one much cared unless the pawns can be used against Israel.
Palestinians who remained in Israel are now citizens with voting rights etc. Israel didn’t chuck them in camps like their neighbours did.
The camps are now cities by the way. But no one calls them that, cause “camps” is better to use against Israel.