Did cummins come out in Ford trucks?

The development of Cummins engines and the establishment of the company has nothing to do with Ford. As for using their engines, yes, Ford has used Cummins engines, in some of their medium duty trucks (currently represented by the F650 and F750... the F450 and F550 are also medium duty, but the Cummins engines were never available for those... the heavy duty market, Ford gave up in 1997 and sold to Daimler A.G., who put the trucks into production under the Sterling name.