Volo is an NPC in Baldur’s Gate 3, particularly a writer who belongs to the human race. Besides BG3 he has shown his appearance in various other games as well, mainly working as a historian and writing stories related to different monsters. In BG3, Volo gets captured multiple times by different enemies because of his habit of getting involved in everything and it is up to you to rescue him.
While going through Act 1 and Act 3 of the game, you have the option to rescue Volo from the enemies or let him face imprisonment for his obstinate behavior in BG3. Well, adopting the former option will help you get some rewards.
Volo has knowledge of surgery as well (sort of) and he will offer you his help to remove the parasite from your brain surgically. He will also give you a book titled Volo’s Guide to Monsters. Reading it can provide a permanent +2 bonus to all attack rolls, ability checks and saving throws.
How to rescue Volo from the goblin camp in Baldur’s Gate 3
Your first encounter with Volo will take place in Druid Grove during Act 1 where he will be found interacting with a bear just after the battle with the Goblins. He will inquire about some information related to the goblins so he can know about True Souls and The Absolute in BG3.
Even after refraining from visiting the Goblin camp, he tries to approach them which results in his imprisonment by the Goblin group at the Goblin Camp.

In order to rescue Volo in BG3, you need to visit the Goblin Camp in a friendly manner. It is located near the Blighted Village west of Druid Grove. Once inside, you will see him performing on a stage in front of the goblins, including their head Gribbo.
Upon the arrival of your whole party, he will get confused while performing and this will cause suspicion to Gribbo. She will immediately send him to the cage at the Shattered Sanctum. This will start the Rescue Volo quest.

The first objective of completing Rescue the Volo quest in BG3 is to find Volo’s location where he is. You need to enter the Shattered Sanctum using the Heavy Oak Door in the same room where Volo was performing. Once in the next hall, move straight, and a few steps ahead you will find a staircase on the eastern side.
Climb up the stairs and enter the door on the far left in front of you. Here you will find Volo in the cage along with the Goblin Gribbo guarding the cage. X: 334 and Y: -9 are the exact coordinates for the cage.
Reward
Now to take him out of the cage, you can either persuade Gribbo using Deception, Intimidation, or Wisdom check or you can have a fight to kill her. Both ways you will end up rescuing Volo in BG3. Talk to Volo and instruct him to meet you at the camp. When you visit the camp, he will reward you with a Blazer of Benevolence. Volo will also offer to perform an eye surgery on you to remove the Illithid parasite.
You can deny the offer but accepting it will result in an unsuccessful surgery causing your character to lose one eye permanently. For the loss, you will get an artificial eye and a passive feature known as Volo’s Ersatz Eye as a gesture of apology from Volo. This feature will help you see the invisible things in your surroundings up to 30 feet.
How to save Volo from the mob in Lower City in BG3
While going through Act 3 in BG3, you will find Volo tied to a rail cart on a track in the Southwestern part of the Lower City area. X: -229 and Y: -172 are the exact coordinates for the rail cart. He is tied to some large explosives, and you need to free him.

To free Volo you need to use Help Action. But this requires you to reach the rail cart surrounded by enemies. You can use the Misty Step spell to teleport the character near the cart. Once he is freed, the explosives will burn out destroying the cart. You can fight the remaining enemy mob to free up the whole area. This is the whole rescuing procedure of Volo for Act 3.