Yes, it can affect your current visa, especially if it's a nonimmigrant visa like a tourist (B-1/B-2), student (F-1), or work visa.

If you apply for a green card while on a nonimmigrant visa, you're signaling immigrant intent, which may conflict with your visa's purpose.

If you marry a U.S. citizen and apply for a green card, you may be able to adjust your status in the U.S., but USCIS will look at your entry intent.

If you overstay your visa and you're married to a U.S. citizen, you may still be able to get a green card—but not if your spouse is only a green card holder.