Periodically, an opening line experiences a spate of popularity in grandmaster practice. Something like that is currently happening with the Four Knights English line in which Black opens the center with an early … d7-d5.
Starting popularly with Rubinstein, over the years the second player has often aimed for a reversed Maroczy Bind, commencing with move orders like 1. c4 Nf6 2. Nc3 c5 3. g3 d5 4. cxd4 Nxd4 5. Bg2 Nc7, planning … Nc6 and … f6/e5. White can short-circuit this classic plan in a number of ways, e.g., 3. Nf3 d5 4. cxd4 Nxd4 5. e4 or 3. e4 or even 2. Nf3 c5 3. d4, all of which lead to interesting lines playable for both sides.
The original Rubinstein plan is not frequently seen nowadays. The latest trend when Black opens the center early is towards a dynamic Black fianchetto position which can be reached most directly via 1. c4 c5 2. Nf3 Nf6 3. Nc3 Nc6 4. g3 d5 5. cxd5 Nxd5 6. Bg2 g6. This position occurred three times in the recent Leko-Li Chao match in Hungary, and a few days later popped up in a more roundabout move order in the 2015 Sinquefield Cup going on right now in St. Louis, Missouri. It is well-known, but hardly mined out, as the games in question illustrate.