Apple has investigated this over the years, even getting as far as building a red board prototype 3G MacBook Pro in 2007: https://www.cnet.com/news/apple-wants

Apple has investigated this over the years, even getting as far as building a red board prototype 3G MacBook Pro in 2007: https://www.cnet.com/news/apple-wants-its-3g-macbook-prototype-back/ https://www.cnet.com/news/apple-wants-its-3g-macbook-prototy... (Green and blue boards tend to be for production-ready prototypes, red is fairly hacked together.) I believe the objections are 50:50 software-related and battery. How do you set suitable data usage thresholds on a Mac which is running over a 3/4/5G LTE network? The thermal performance of MacBook Pro is already weak at the high end and battery life suffers. I would be surprised if, when Apple switches to its own power efficient chipset in its portable Mac line, they don't offer a BTO option which includes cellular capabilities through a built-in SIM.