From May 23th to June 12th you will be able to participate in the Overwatch’s anniversary event! Three new arenas for arcade, new skins, voicelines, emotes, dances and more! If you log in during this time you’ll also get a free event loot box. The event is playable on PC, PS4 and Xbox one. Check out for more information on their official website.
Just a side note: there will be a free weekend starting from May 26th 11 AM PT to May 29th 11:59 AM PT.