Season the pork shoulder with salt, pepper, cumin, and cinnamon, massaging the spices into the meat for even coverage.
In a large skillet, sear the pork shoulder on high heat until each side develops a deep golden brown and releases a rich aroma, about 3-4 minutes per side.
Transfer the seared pork to your slow cooker, add the roasted garlic cloves and pour in the chicken broth to provide moisture and flavor.
Cover the slow cooker and cook on low for 6-8 hours, until the pork is fall-apart tender and shreds easily with a fork.
While the pork cooks, prepare the slaw: core and thinly slice the apples and fennel bulb, then combine them in a mixing bowl.
Whisk together the apple cider vinegar and honey, then toss the mixture with the sliced apples and fennel to coat evenly. Let sit for a few minutes to allow flavors to meld.
Once the pork is cooked and tender, remove it from the slow cooker and shred it using two forks, discarding any excess fat or gristle.
Warm the tortillas in a dry skillet or microwave until soft and pliable, about 20 seconds.
Assemble the tacos by spooning generous amounts of shredded pork onto each tortilla, then top with a handful of the apple fennel slaw for crunch and freshness.
Serve the tacos immediately, with optional extra dressing or fresh herbs if desired.