Hmm, Ground Elder is something I've looked into regarding an unidentified plant in my yard... But my plant looks nothing like the OP's pictured leaves. But I see in many of the photos in a google image search, that apparently there might be some variance in the appearance of the leaves.
What exactly would be an identifying trait of ground elder then?
I'm seeing that Ground Elder may come in both variegated & not variegated leaves...
Does bishop's weed also come in variegated & solid?
The bishop's weed in my yard does NOT resemble the OP's photo at all.
Even if my bishop's weed was solid green, the shape of the leaves and appearance of the stems & configuration are nothing like that.
I could see how the plant pictured in the OP could be mistaken for poison ivy. It has a resemblance to the general plant/leaf configuration.
I've never reacted to any poison ivy,
Not that I would wish to be sensitive to poison ivy just to have a chance at a positive ID. lol
But for example, the poison ivy at my family's cottage, that grows on the riverbank and such looks rather different than the poison ivy in the woods at my MIL's house in the mountains. And to be honest, both kinds I could easily miss as important. I've nearly, or definitely, walked through it (sometimes with sandals), only later to have someone point it out, or tell me they got a rash!
So I'm still not quite sure how to spot it well.