The Crypto Forum Research Group of the Internet Research Task Force has developed Hybrid Public Key Encryption (HPKE), a new standard for public-key encryption in internet protocols and applications. HPKE is designed to be simple, reusable, and future-proof by building upon knowledge from prior PKE schemes and software implementations. It is already in use in emerging Internet standards such as TLS Encrypted Client Hello and Oblivious DNS-over-HTTPS, with interoperable implementations available in libraries like OpenSSL, BoringSSL, NSS, and CIRCL. HPKE's generic construction allows it to adapt to a wide variety of application requirements, making it an essential part of the future of internet security protocols.