If you want to get a look at the new map then you should go play PTR Overwatch right now. Eichenwalde, the new map, was revealed earlier this month and is now available to be played on the PTR servers. To get to PTR servers you have to select PTR: Overwatch from the region menu. Then download the client and the new map, and all the other season 2 changes, are yours to explore. I myself really like the map so far.
Currently the map only comes up in normal rotation in Quick matches and Competitive matches. But you can always load up a custom game to explore the map at your leisure. Without having a team get mad at you for abandoning them for your adventures. Eichenwalde is an old German castle that was the site of a massive battle during the Omnic crisis. In the battle the Crusaders fought against a overwhelming number of Omnics before finally being defeated. The leader of the Crusaders, Baldrich Von Alder died during the battle. His remains are clearly visible at the final point of the map. Reinhardt is also from the Crusaders, a now defunct paramilitary group.
In the map you have to escort the payload, in this instance its a battering ram, to its destination, which is a gate, and then capture a point beyond the gate. This is the first reverse hybrid map in Overwatch. It is going to be interesting to see how this will play out in the coming days. Already season 2 is looking like it is going to be a major improvement on the first season. We went over all the upcoming changes to the game in here and here. This map is going to inject much needed variety into a game that could quickly become stale. Blizzard has done a wonderful job in preventing the game from going too long without any changes or new maps/characters.
In this patch there are also 2 new Legendary Skins available for Reinhardt.