This will be the first major update for Monster Hunter World. It will be coming soon and will be available for all regions.
The update will be released this March 22nd. It introduces Deviljho, a new monster that devours everything that crosses its path. And the Spring Blossom Fest which is a festival for players to take part in which will also involve a lot of monster hunting. The introduction of paid appearance change tickets will be introduced to the players. Each player will receive 1 free ticket for their own use.
This update will also introduce balance changes for a lot of weapon types as well as give them new features.
This March update info was introduced through Famitsu Website and shared through English patch notes. We have yet to receive more info if it has anything more to offer.
Source: Capcom-Unity