As per Cardano’s software rules, there is a finite number of ADA, which is set at 45 billion. Moreover, as of June 2021, according to the CoinMarketCap, there are over 31.95B ADA in circulation. Thus, Cardano is in 12th position in the list of cryptocurrencies with the most coins. Such caps are considered to be one of the means to reduce the inflation rates of cryptocurrencies over time.
Although Cardano can't be mined, it can be staked because it is using the "Proof of Stake" system.