Argon2 is a cryptographic hashing algorithm that won the Password Hashing Competition in 2015. It is known for its resistance against GPU-based attacks and its ability to use both CPU and memory resources efficiently. In addition to password hashing, Argon2 has applications in key derivation and data integrity verification. It allows users to adjust its parameters to balance performance and security based on their specific needs, making it suitable for a wide range of applications in modern cybersecurity practices.