He's a business mind who made a name for himself when he joined a mobile technology startup, but his first company focuses on skin and hair care. He grew up in a working-class family in New York, and his father was killed when he was young – but he went to a boarding school.

His most prominent investors? Andreessen Horowitz, the marquee Silicon Valley venture capital firm – but he and I speak plainly about Silicon Valley's diversity challenges.

I recently visited Tristan Walker at the offices of Walker & Company Brands in Palo Alto, California, the heart of Silicon Valley. This episode was special for me, because, let's be frank: There aren't many African-American technology journalists in this business. I'm one. There aren't many African-American entrepreneurs in Silicon Valley, and Tristan is arguably the best-known. I'm seven years older than Tristan, but we're of a similar generation. We've been a part of this era of sweeping change, and seen what's missing ... and who's missing.