Expansion site: https://www.guildwars2.com/en/secrets-of-the-obscure/
Trailer: Click Here
Announce Blog: Click Here
Combat Updates: Click Here
Story, Mastery and more updates: Click Here
ThatShaman Countdown: Click Here
After the Dragon Cycle - Guild Wars 2 News: Click Here
First Contact: The Kryptis and Rift Hunting: Click Here
Blog post with Roadmap here