An oak of some sort?

Then there is a wild lavatera that resembles that too.

Assuming you're in California it's a Fig. They commonly self-sow in the
wild there.

I agree with Fig. All figs have milky sap...a quick and easy way to back up the id. As with all milky sap, avoid skin contact in case of sensitivity.

Leaf shapes vary, I am sure you will find this has the same sap and odor as the other kind.

A single fig tree can have several differently shaped leaves at the same time. ID'ing them is tricky and usually requires seeing the fruit also.