Thanos decimated the Marvel Cinematic Universe during the events of Avengers: Infinity War. Using the combined power of the six Infinity Stones, the Mad Titan snapped his finger and obliterated half of all life in the known universe--leaving the Avengers powerless to stop his massive crusade.
Source：https://www.cbr.com/mcu-characters-nothing-to-help-against-thanos/
