By default, classic HTTP (a layer 7 protocol) uses TCP (a layer 4 protocol) as it’s base.
To solve speed issues with TCP and encryption with it, Google created SPDY, a protocol that fixed some of TCP’s problems. HTTP-over-SPDY protocol eventually became the official HTTP/2, which is now used on around 40% of all internet sites.
Later Google engineers realized they could do much better if make a totally new protocol. That’s how QUIC came to be, or “Quick UDP Internet Connections.”