The official synopsis for Thanos: Titan Consumed reads as follows.
Thanos: Titan Consumed, by Barry Lyga, is set well before the events of Infinity War and will tell the backstory of the super villain.
The Marvel Cinematic Universe is expanding into books with the release of Thanos: Titan Consumed.
The book is the first of its kind for the MCU and will be an official tie-in canon story to compliment the upcoming Avengers: Infinity War and flesh out the villain before the release of Avengers 4.