CMC has new features, which I guess they evaluate on their own, but before it was really different as exchanges are only ranked based on its 24 hours trading volume, but due to some exchanges faking its volume, CMC are making their own evaluation by adding some factors to determine the overall ranking of a site.
The 24-hour trading volume reflected on CMC prior to Binance acquiring it was segregated between "Reported" and "Adjusted." This was a way for CMC to somehow counter the questionable volume figures reported by the exchanges themselves. Binance not only disregarded this, it also removed it altogether and shifted into another metric of ranking exchanges by which Binance will rise to the first rank.
This is the start of a Sun and a Zhao squabble.