Maybe a Smilax species but I've never seen any of them in the flesh so I can't be more precise.

Smilax bona-nox, Greenbriar.

I have them everywhere (D/FW). Leaf shapes can vary, but I’m positive that's what yours is.

It was there last year, you just now noticed it. That's not a first year sprout. Dig up the tuber to remove it.

Thank you. Yes, it could be a repeat, but it's in a remote part of the yard, so I might not have noticed it before. I understand that they are invasive, so I guess it might spread. Except it seems to be just one plant, and they are dioecious, so pollination and seed distribution is unlikely. That being said, I understand it's supposed to bloom in the spring, but I see no evidence of flowers or flower buds on this one.

It’s too early for blooms. I usually notice them in May to June here and not for long.

It's an very big vine, likely native. If you have room for it, the birds will enjoy the berries later. As far as seedlings go, yours came from somewhere.

Pretty sure that to the extent birds and animals like the berries, that's who deposited the seeds. As to flowers, Vines, Robert A. 1960. "Trees, shrubs, and woody vines of the Southwest" University of Texas Press. reports flowers in April-June. I'll watch for them, but right now, there aren't even any buds.