this is an unknown grapevine growing along a road in the low country.
I’m afraid I must call this grape Summer grape also, Vitis aestivalis. Some of the grapes, such as this one and Fox grape [Vitis labrusca] can have quite variable leaves. This and the other one you submitted with deeply lobed leaves appear to have identical stems, and this is an important character. Both Fox grape and Summer grape have stem branches that are round in cross section [terete] and this seems to be the case on both grapes that you posted. Summer grape tends to have the soft short hairs more often on the leaves and petioles than does the Fox grape.
Steve Hill, Botanist, SCNPS