It seems that the latest Modern Warfare title, which will be called Call of Duty: Ghosts instead of Modern Warfare 4, will be unveiled on the 1st May.
According to a leak from a GameStop employee, a display for the new game arrived, stating "Call of Duty title. Should arrive by 5/1. Keep 4/8 poster displayed still new posters arrive 5/1. DO NOT DISPLAY TIL 5/1."
UK super-retailer Tesco had spoiled Call of Duty: Ghosts, complete with packshot art.