Despite widespread rumors, Bill Gates, formerly the richest man in the world, has yet to announce a program to implant brain-computer interfaces in the world population. Snopes rated the following claim false:
Bill Gates ... seeks to "microchip" the world population
However, this could easily change. Elon Musk, the world's richest man as of January 2021, has founded Neuralink, which aims to ultimately implant brain-computer interfaces in humans and has already implanted a brain-computer interface in a pig:
Elon Musk has unveiled a pig called Gertrude with a coin-sized computer chip in her brain to demonstrate his ambitious plans to create a working brain-to-machine interface.