I do not believe it is a weed, but that doesn't mean that I can tell you what it is. To me, the leaves and growth pattern remind me of something like pineapple sage. If you rub a leaf gently between two fingers, does it release a scent onto your fingers? Maybe a tropical, fruity scent or perhaps a sage type scent? There are some golden pineapple sage cultivars that do have yellowish-green foliage instead of the darker green foliage more typical of most salvias.

Thanks for the information. I did as you said and this plant did not release any scent. However, I have another plant that looks similar, and when I rub the leaves between my fingers, it released a fruity scent. I had posted this other plant on the forum too. Now I am more convinced this other plant is a pineapple sage. They look very similar except I noticed that the pineapple sage has jagged leaves. Whereas this plant has smooth-edged leaves.

There's different varieties of pineapple sage, so maybe yours is just one of the less common ones. There are some that have a foliage that is more golden than green, but I haven't grown those so don't know if their leaf margins are the same as on the green ones or if their scent is exactly the same. Maybe it will flower eventually and the flower will provide more clues.

Even if it isn't pineapple sage, I bet it is an herb of some sort. It just has that look.

check the stems, are they square? That will tell us if it is in the mint family

To me it definitely looks like something in the salvia family

No, the stems are not square, but thanks all, I think it is a herb too, it does look like in the salvia family.