Difference between cookie and cookieSession?

What is the difference between cookieSession and cookie in express?

The cookieParser middleware parses HTTP Cookie: headers to populate req.cookies (and req.signedCookies if you give it a secret).

The cookieSession middleware adds cookie-based session state.
It depends on the cookieParser middleware to use cookies.

There is no cookie middleware, although there is a cookie package which exposes a utility function that creates or parses cookie strings. The cookieParser middleware uses this package to read & write HTTP headers.