The requirements for a currency to be listed on Coin Market Cap are quite clear. Coin Market Cap has published instructions on listing currencies. Therefore, the transaction volume can not be one of the criteria for listing. Coin Market Cap explicitly mentions this in his latest correspondence.

The text of the message in the last correspondence with GCE: View Document

For trading volumes, there is no specific threshold that we are able to disclose publicly, as we benchmark our assessment against market conditions and other applications.