sanctuary city
noun [ C ] uk/ˈsæŋk.tʃʊə.ri ˌsɪt.i/ us/ˈsæŋk.tʃu.er.i ˌsɪt̬.i/
（美国或加拿大非法移民的）庇护城市
a city in the US or Canada where illegal immigrants (= people who have moved to live in another country when they do not have the legal right to do this) are not prosecuted
Houston is one of the better-known sanctuary cities for immigrants in the US. 休斯顿是美国比较著名的移民庇护城市之一。