I have treated many hundreds of patients with atrophic/depressed boxcar scars with nice results. Typically multiple treatments are required, and multiple modalities. Treatment options depend on many factors including age, skin type, previous treatment experiences, budget, downtime, extent and location of scarring, pain tolerance, etc; It most certainly is not 1-size fits all and requires a proper in-person assessment by a scar expert such as a dermatologist. It is also key that your acne is under good control and/or in remission. I believe that subcision, often with fillers, is a great way to start, followed by subcision alone (usually every 6-8 weeks). Laser resurfacing such as ErYag (Profractional) or CO2 fractionated lasers is also an excellent option, again several sessions (usually every 4-6 weeks). Medical grade & deeper chemical peels can also be helpful, whereas microdermabrasion isn't so helpful. I also very much like microneedling (medical-grade, deeper, although home devices can help a bit too), especially when boosted with PRP (platelet-rich plasma) or RF (radio frequency). For stubborn scars not sufficiently responsive to aforementioned treatments, we do punch excisions. For thicker/keloid/hypertrophic scars, we do cortisone or cortisone-mix injections. Best to chat with your local dermatologist who has the most experience and training in treating both acne and acne scars.