Preheat a smoker to 250°F. Add the soaked hickory wood chips according to the smoker’s instructions so it is ready to produce steady smoke.

In a small bowl, stir together the breadcrumbs and milk. Let them sit for a few minutes, then mix in the egg, diced onion, Worcestershire sauce, salt, and black pepper.

Add the ground beef and gently mix until the ingredients are just combined. Avoid compacting the meat, which can make the loaf dense.

Place the meat mixture on a sheet of parchment and pat it into a rectangle about ½ inch thick. Spread the softened cream cheese down the center, leaving a border around the edges. Fold the meat over the filling and pinch the seams and ends closed. Shape the loaf seam-side down.

In a small bowl, combine the ketchup, apple cider vinegar, and brown sugar. Brush about half of the glaze over the meatloaf, reserving the rest for later.

Set the meatloaf on a smoker-safe pan or directly on a clean smoker rack. Smoke at 250°F until the center reaches 160°F, checking with an instant-read thermometer inserted into the meat rather than the cream cheese filling.

Brush the remaining glaze over the top during the last 15 minutes of smoking. Remove the meatloaf when it reaches 160°F and let it rest for 10 minutes before slicing.