It's hard to overstate Intel's importance in regards to the modern CPU: they invented the microprocessor itself. (Though I'd like to state it's a bit controversial whether they only were the first to come up with a commercially available one or whether they actually invented the concept itself)
Also, there are many things outside the CPU that we take for granted today that were of Intel's innovation. A great example would be PCIe that Intel invented and essentially standardized. More recent example would be USB4.
Regarding CPUs they have some truly legendary chips, like the Intel 8086. This chip from the 70s is still in use today in your everyday products (as a clone though). It can be found TODAY in common products like computer mice, keyboards, AC, TV remotes and so on. Anything that is a commodity and needs some simple processing power has usually some derivative of 8086 inside it, granted ESP32 and such are taking over nowadays.
Of course the x86 instruction set comes from that very chip. I guess the name speaks for itself how big of a thing that was.
There's too much to fit inside one comment about how innovative Intel truly used to be, but they have a pretty good page for their history here: https://timeline.intel.com/