Adobe Analytics won't capture any campaign tracking code until you have configured the Util.getQueryParam. The configuration involves letting Adobe Analytics know what parameter to look for in the URL (e.g. "cid"), referred to as the "key". If there are multiple query parameters in the URL separated by ampersands, Adobe is only going to grab the values associated with the query parameter that you've told it to look for.
For example, let's say that you've configured Util.getQueryParam to look for "cid", and to store the value associated with the "cid" key in the s.campaign variable (s.eVar0). if the URL for one of your campaigns is mysite.com/?cid=new_campaign&eid=other_campaign, only the value associated with the cid parameter, new_campaign, will be captured.
For another example, let's say that the campaign URL is mysite.com/?cid=new&campaign. The presence of the ampersand tells Adobe to stop because the ampersand is Adobe's default delimiter. In this case, the value captured in the s.campaign variable is "new", and the "campaign" part is not captured. You can specify a different delimiter, such as semi-colon, in the Util.getQueryParam configuration.
ampersands are how query strings are separated. If you have the URL https://example.com?cid=value1&did=value2, you could use the query string param utility to extract either value1 from cid or value2 from did.