Polkadot doesn't run smart contracts

Polkadot and Kusama are completely separate networks from Ethereum, BSC, Polygon, etc, which is why there are no contract addresses like you may be used to with ERC20 and BSC20 tokens. 

Polkadot parachains are designed to be application-specific, as they are custom-built for a specific use case. While many parachains can run smart contracts, the Polkadot relay chain itself does not have them. Instead, the relay chain is a layer-0 protocol that connects these parachains together through shared security.

Therefore DOT and KSM are currently not available on Uniswap, MetaMask, Pancakeswap or other projects of the Ethereum or BSC ecosystems. 

There are "wrapped" or "pegged" tokens on both networks for both DOT and KSM, but these are not native tokens. They simply represent DOT or KSM, but they can't be sent to native Polkadot or Kusama accounts.

IMPORTANT: The contract address shown on sites like CoinMarketCap, is for DOT-pegged (wrapped) tokens running on other networks, as mentioned in the banner on top. Don't confuse this with polkadot's native DOT token.

IMPORTANT: Be aware that there are also scam tokens on both networks! If you need to use these wrapped tokens, verify first that you are interacting with a legitimate contract, as anyone can create a smart contract and name it whatever they want.