The MP944 was the ‘real’ world’s first microprocessor, but it was top secret for nearly 30 years — F-14 Tomcat's chip lived in the shadow of the Intel 4004, but was eight times faster

https://www.tomshardware.com/pc-components/cpus/the-mp944-was-the-real-worlds-first-microprocessor-and-key-to-the-flight-of-the-f-14-tomcat-but-it-lived-in-the-shadow-of-the-intel-4004-for-nearly-30-years