A Reddit user noticed that Loki’s official bio on Marvel.com was quietly updated at some point and now confirms a theory that has been floating around for some time. According to Loki’s updated bio, Thanos offered Loki dominion over Earth, which would allow him to get back at Thor, in exchange for Loki getting Thanos the Tesseract, which we now know to be the Space Stone.
Article source: https://www.cinemablend.com/news/2464296/marvel-updated-lokis-official-bio-and-now-we-have-to-rethink-everything