Without any other clues (size, growth habit, etc) I can't, other than to point towards maybe Sorbus, Rhus, Rowan, possibly a variety of ash, as possibilities, although Rhus should by now have started changing colour,along with evidence of autumn on all the others, which is not visible here. Need a photo of the whole tree, bark and close up of an actual branch with leaves and any keys, seedcases, fruits or berries if possible.

Agree with Bamboo, impossible to give an i.d. from a single stem of leaves.

my first thought was ash but all the others listed are possible too.

Looking at the heel where the leaf has detached from the twig I would say ash. The other information previously asked for would be useful to confirm.