[Update: Respawn has confirmed Zampella's departure, stating that "Jason has left Respawn to take care of some family issues."]
The termination of Infinity Ward's Vince Zampella and Jason West from the Activision payroll back in 2010 was a very public, very ugly situation. There were lawsuits, allegations, counter-allegations, and bitterness to spare. The only upshot of the whole thing was that West and Zampella went to form a promising new studio called Respawn Entertainment. Ironic, considering that Activision was formed under similar circumstances by disgruntled Atari developers back in the 1979.
Reports are now pouring in that West has left Respawn. No official statement has been released, but word is going around that West left the studio back in 2012, but has not yet made this departure public. Other reports state that he's left the studio on good terms to spend more time with his family, and that he may be retiring from all game development employment, at least for now.
There's also no official word on what will become of Respawn's planned title for EA, though reports state that it'll make an appearance at E3 this year.