The Galaxy S9 may be announced at MWC 2018 in February
http://www.techradar.com/news/the-galaxy-s9-may-be-announced-at-mwc-2018-in-february
Samsung has a long history of announcing its flagship phones at Mobile World Congress, and despite skipping it in 2017 it seems the company may be set to announce the Galaxy S9 and Galaxy S9 Plus at the 2018 event.
A new report from Korean website The Bell has suggested Samsung is set to have an event at the MWC 2018 show at the tail end of February next year.