Hi and welcome! I'm not sure what it is, but it looks like the flowers are about to open so that will make identifying it much easier. Could you possibly wait until the flowers are open then post another picture?
Btw, the true definition of "a weed" is any plant growing where you don't want it. So if it turns out to be something pretty and you like it, you can keep it anyway. I have "weeds" in my garden that are lovely pink salvias. They seed themselves here and there all over my garden, and I leave them in places where they look nice. I also have milkweed that seeds itself and I try to keep as much of it as I can for the butterflies. So although these might be thought of as weeds because they seed themselves and randomly pop up unplanned, they really are not weeds to me.
Please would you complete your personal profile so we know where you live? It's so much easier to ID plants and answer questions if you know the location.
