The US Army has an exceptionally well-crafted field manual on leadership. No fluff, but also no chest-thumping. It's honestly the best resource I've ever seen on what constitutes a good leader, how good leaders are developed, and how good leaders develop their teams. Being a DOD publication, it's in the public domain: https://usacac.army.mil/sites/default/files/misc/doctrine/CD... I can't stress enough how excellent…
The military is an org that has a chain of command in which strict adherence to orders from your superiors is a question of life and death. I don't know if it's a good idea that managers in an office environment attempt to emulate the military.
But people are people, communication is communication and at the end of the day, regardless of what else they are, armed forces are large complicated organizations. It would be foolish to assume that because your organization(s) have different goals and mandates, they have nothing to learn about communication, leadership, training, etc. from decades (at minimum) of well documented armed forces experience.