No idea, but even the Marlboro Man died of cancer from smoking. The suffix “boro” usually means town, so maybe it’s a town’s name like Greensboro, Goldsboro, Hillsboro, etc… According to Wikipedia (which isn’t the best source) Marlboro brand cigarettes is named after Great Marlborough Street, the location of its original London factory (now changed to Richmond Virginia).
This may be totally crazy but when I was a teenager (not so long ago, am only 21) I used to smoke and my friend told me the Klu Klux Klan had shares in Marlboro and if you study the packet you can find three gold K’s(for lights) and 3 red K’s (for full flavour). This is true as you can find them.One on the top, one on the front and one on the back. Also,this same friend told me that when you turn the packet upside down and read the writing backwards, it spells ‘orobl jew,’ which can be interpreted as ‘horrible jew’!I don’t really know, but when he showed me, I could see it. I wouldn’t take his word for it though as it was a few years ago and I was gullible. A cigarette brand based on ‘white supremacy’ seems ridiculous, but then again so is the KKK!Hope you enjoyed my comment!