There is few official announcement usually in summer during the hot vacation time, but in this summer 2015, it seems Panasonic, Olympus and Sony will have their announcements!
Panasonic: Panasonic GX8 and a new MFT lens are rumored to be announced by end of July!
Olympus: They will announce the Olympus E-M10 Mark II in August!
Sony: The delayed Sony A7000 cameras is also rumored to be coming in August already!
Stay tuned for more info.