Title says all. This is purely 100% out of curiosity and by no means meant to offend anyone. Problem is, I very rarely see 人外 used anywhere.
人外【じんがい】 is an uncommon and old-fashioned word. In fictional works, it typically refers to evil monsters, undeads, Japanese yokai, etc. You won't see this term often unless you're a fan of fantasy. Dictionaries say it also means "evil/wicked", but from my experience, it's rarely used in this sense. 外人 means a foreigner. 人外 is an anagram of 外人, but this is basically just a coincidence and you should not feel anything special here. There are many similar pairs in Japanese.
With that being said, there was a time (30 years ago or so, if I remember correctly) when 人外 was used jokingly as a slangy term for 外人. Wikipedia says this was a (sarcastic) reaction to the "外人 is derogatory" movement. No one is using 人外 in this sense anymore, and you can safely forget this trivial fact.
Technically speaking, 人外外人 — but not 外人人外 — might mean "foreigner who is no longer a human" or "highly immoral foreigner", but since 人外 itself is an uncommon word, I haven't seen something like this.