The deployment of multicall3 contract on IoTeX network is 
0xcA11bde05977b3631167028862bE2a173976CA11
The deployment of multicall3 contract on IoTeX Testnet is 
0xb5cecd6894c6f473ec726a176f1512399a2e355d

​
References

Multicall3 contract on IoTeXScan: https://iotexscan.io/address/0xcA11bde05977b3631167028862bE2a173976CA11 Multicall3 contract (Testnet) on IoTeXScan: https://testnet.iotexscan.io/address/0xb5cecd6894c6f473ec726a176f1512399a2e355d Multicall3 website: https://www.multicall3.com/deployments