What is the difference between running a local host with npm or pnpm?

Question

I'm in the console log and I want to execute my program with pnpm run dev, and it doesn't work, and looks like:

+ CategoryInfo          : ObjectNotFound: (pnpm:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

I just want to generate my localhost like always but instead of npm with pnpm