Heroes of the Storm Season 4 or like Blizzard calls it Season 1 2017 started 13.March.2017 and ends 13.June.2017
There wont be any major changes these season.
If you get to Platinum division in the season you will earn the mount too :
Other rewards are:
Bronze 500 Gold Bronze Hero League Portrait
Silver 750 Gold Silver Hero League Portrait
Gold 1000 Gold Gold Hero League Portrait
Platinum 1250 Gold2017 Season 1 Mount *Platinum Hero League Portrait
Diamond 1500 Gold2017 Season 1 Mount *Diamond Hero League Portrait
Master 1750 Gold2017 Season 1 Mount *Epic 2017 Season 1 Mount *Master Hero League Portrait
Grand Master 2000 Gold2017 Season 1 Mount *Epic 2017 Season 1 Mount *Grand Master Hero League Portrait
Thoso are the rewards for Hero League, Team League has exactly the same rewards just the icon is diferent.
In addition to everything we’ve mentioned so far, there will be 10 placement matches waiting for you on the other side of the season roll that you’ll need to play through in order to receive your initial ranking.
And dont forget if you need any help in Heroes of the Storm we are here for you.