dcbstatic.com - is it a cookie ?

"Doesn't remove", or comes back? If the latter, then a web site you typically visit is putting that cookie back every time you visit that site.

And cookies are nothing to worry about. Delete them all if you want, though afterwards you may find you have to re-enter some web site logins. Or, if you had items in a basket at Amazon waiting to be purchased, it will be empty since a cookie holds that information.

Where did you saw that cookie?

In Safari:

Safari > Settings ... > Privacy > Manage Website Data ...

wait until list populate ...

• select cookie then click Remove

Do it a few times.