A more thorough explanation:

The inevitability doctrine is a legal theory that applies to trade secrets. It suggests that a former employee who has access to confidential information of their previous employer cannot avoid using that knowledge to unfairly compete against the former employer once they are hired by a competitor.

For instance, if an employee of a company that produces a unique product leaves and joins a competitor, they may use the knowledge they gained from their previous employer to create a similar product. This could result in the former employer losing their competitive edge.

The plaintiff must prove that the former employee has confidential information and will not be able to avoid using that knowledge to unfairly compete against the plaintiff. However, most courts have rejected this doctrine because it turns a nondisclosure agreement into a noncompetition agreement.

One of the leading cases that upheld the inevitability doctrine is PepsiCo, Inc. v. Redmond, 54 F.3d 1262 (7th Cir. 1995). In this case, the court compared PepsiCo to a coach whose player left with the playbook to join the opposing team before the big game.