Pork is known for drying out easily, but tenderloins are easier to keep moist. First, avoid overcooking it. While it is baking, check the temperature often. It can go from “not quite done” to “super dry” in just a few minutes. The pork will continue to cook for a few minutes in the pan before you slice it, so remove it 3-5 degrees below the target temperature. Second, if you aren’t serving the best pork tenderloin immediately after slicing, loosely cover it with tin foil. This will trap the moisture and prevent excess air exposure from drying it out.  Third, drizzle sauce on top to keep it moist.