"Repatriation of fugitives to their home countries" 或 "Sending fugitives back to their native countries" 都可以表达“亡命者送还本国”的意思。其中,“repatriation”意为“遣返;送回本国”,更正式一些;而“sending...back”则更为直接和通俗。具体使用哪个表达,可根据语境和正式程度来选择。