That is that this season Exile Island is in play. It will work like this, the tribe that wins the immunity challenge will then decide someone to send to Exile Island. That essentially makes that person immune from the vote as they will not attend tribal council, so cannot be voted out. They will then rejoin their tribe after the Tribal Council has taken place.
So you will need to think about who you might like to send to Exile Island. There needs to be a majority agreement, and the way it will work is that during the challenge each of you need to message me the name of the person that you would like to send to Exile should your tribe win the challenge. If there a majority of the tribe agrees then that person will be sent to Exile, if there is no majority it will be decide by random.org
This decision could be very important in helping you later on in the game because the person that goes to Exile Island will also have the chance to search for a hidden immunity idol.