Very little is known about the Sentinelese as they have vehemently refused all attempts of contact from the rest of the world and insisted on remaining isolated. They occupy North Sentinel Island and are known to be hostile to anybody attempting to associate with them. Multiple fly-bys and other attempts to make friendly contact with them have been made but they have refused to let outsiders get close to them. The exact number of Sentinelese people is unknown as long-term contact with the tribe has been virtually impossible.
The Jarawa is the Andaman islands tribe that has been most receptive to outside contact. They have been known to voluntarily seek medical assistance in cases of emergency. There are around 200-400 Jarawas who subsist on fishing, hunting and foraging. There are records of regular contact being made with the Jarawa since the 1970s. The Great Andaman Trunk Road - commonly known as NH 4, was constructed on land that previously belonged to the Jarawa. This move almost forced them to regularly interact with the other residents of the islands.
The Onge tribe resides in Little Andaman and is also friendly to outsiders. They are semi-nomadic and depend on hunting and foraging for sustenance. They have been regularly contacted since the 1950s and have since accepted gifts like sugar, tobacco and clothes, among others. Lack of land for hunting has led to some sections of the Onge tribe settling down in one location and practising agriculture. There are around 100 remaining Onge, while the rest have fallen prey to epidemics like measles.
First contacted in the 1840s, the Shompen are one of the most populous tribes of Andaman Nicobar island. There are around 200-300 Shompen who mainly reside on Great Nicobar Island. They have not been very receptive to the outside world, so there is no knowing how many have survived epidemic outbreaks, COVID-19 etc. They are primarily hunter-gatherers.