Fox will be cancelling King of the Hill after its current 13th season finishes. Co-creator Greg Daniels has moved on to The Office, while the other co-creator Mike Judge will be working on another animated series The Goode Family for ABC.
For its part, Fox will be launching two new animated series for midseason: The Cleveland Show (a Family Guy spinoff) and Sit Down, Shut Up. Presumably, the network will try to keep the Sunday night animated block alive.
Source: Hollywood Reporter