"뭐든사람사는냄새가좋다" => 뭐든 사람 사는 냄새가 좋다 == 무엇이든지 사람(이) 사는 냄새가 좋다.
=> Whatever it is, I like the smell of people living
=> I like any smell of people going about their lives.
- 무엇이든 (whatever it is) 사람이 사는(of people living) 냄새가(the smell) 좋다(I like it).
냄새 means 1) a smell, or 2) the outward signs and indications given off by people or things.
Here it means the appearance and signs of people going about their daily lives, like the sight, noise, interactions, etc.
냄새 can also mean a suspicious sign, or a hunch one gets about something.
- 뭔가 수상한 냄새가 난다: There is a suspicious / I smell something fishy.