This is from their FAQ section:

What is the criteria for a cryptocurrency to be listed on CoinMarketCap?

The criteria for a cryptocurrency to be listed is the following:

- Must be a cryptocurrency or a crypto token.
- Must be on a public exchange with an API that reports the last traded price and the last 24 hour trading volume.
- Must have a non-zero trading volume on at least one supported exchange so a price can be determined.
- For market cap ranking, an accurate circulating supply figure is required.

If you'd like to have a cryptocurrency listed and it meets all of the criteria, please fill out the request form at https://coinmarketcap.com/request/.