What is it
There are four domesticated species in the genus Cucurbita:
Cucurbita argyrosperma, Cucurbita maxima, Cucurbita moschata, Cucubita pepo
Based on leaf shape we think it's probably Cucurbita pepo or Cucurbita moschata. Both species include pumpkins and winter squash. Cucurbita pepo also includes summer squash.
Cucurbita pepo has five-sided fruit stems and the leaves and stems are hairy.
Cucurbita moschata has smooth, angular fruit stems and leaves are large, lobed, and often have white spots.
It may be especially hard to identify if it's a volunteer that resulted from the cross-pollination last year of two cultivars of one of the two species mentioned above.jt