Indian Coast Guard
There's an isolated tribe living on a tiny island in the Indian Ocean, and they want nothing to do with modern society.
The people of North Sentinel Island, called the Sentinelese, are considered an "uncontacted tribe," meaning they have little to no contact with the outside world.
They've never developed agriculture - they still practice hunting and gathering, like all humans did prior to the development of agriculture about 10,000 years ago. There's been so little contact with the group that very few photos exist, beyond those taken far from shore or from the air.
But unlike uncontacted tribes hidden away in places like the Amazon Rainforest, we've known about the Sentinelese for centuries, and they want nothing to do with us. They have violently rejected contact with the groups of various nationalities that have attempted to communicate with the tribe, from colonial European explorers to the Indian coast guard. Other than a few isolated trips by anthropologists, they've greeted visitors - and shipwreck survivors - with arrows.
As an important caveat, referring to tribes as living outside of "modern society" is a bit of a misnomer, since all cultures on earth today are modern cultures - technological advancement not required.
Here's how the Sentinelese have managed to ward off outside society for so long.