Preheat your pellet smoker to 225°F.
Trim the beef tenderloin of any excess fat and silver skin.
Combine ingredients to make a wet rub (garlic, salt, black pepper, thyme, and olive oil) and rub the mixture all over the beef tenderloin, covering it evenly.
Place the seasoned beef tenderloin on the smoker grate and smoke for about an hour or until it reaches an internal temperature of 10°F under the desired doneness temperature. (125°F for medium rare)
Once the beef tenderloin reaches the desired internal temperature, remove it from the smoker.
Heat a cast iron pan over high heat with olive oil.
Sear the beef tenderloin for about a minute on each side until it reaches the desired doneness temperature. (135°F for medium rare)
Let the beef tenderloin rest for a few minutes before slicing and serving. Enjoy your delicious smoked beef tenderloin!