Who is setting cookie in Request object on call to server controller

I have a code from Github (aspnet-core-3-signup-verification-api). On the authentication in the controller the refreshToken is set correctly like below:

 Response.Cookies.Append("refreshToken", token, cookieOptions);

But then when the refresh token function is called by the client the following server code :

var refreshToken = Request.Cookies["refreshToken"];

... returns null in refreshToken. I am using Chrome browser. Who is responsible from setting the refreshToken cookie in Request object (I thought it was browser - which in my case is Chrome)