From the informative New York Times obituary:
"Charles M. Schulz, the creator of 'Peanuts' and a Northern California resident, met Mr. Turner in the early 1960s and became a friend and mentor, said Andrew Farago, curator of the Cartoon Art Museum in San Francisco. 'They were the same age, they both were in the war — they just clicked,' said Mr. Farago, who has curated shows of both men’s work. In a conversation one day, Mr. Turner lamented the lack of black characters in newspaper comics, and Schulz suggested he try to do one..."
From a recent profile by R.C. Harvey in his Rants & Raves column:
"All the while, he mulled over an idea for a comic strip. Peanuts particularly engaged him, and then once when Charlie Brown appeared in a Civil War cap, Turner pondered: What if Charlie Brown were Black? And what if the cap were a Confederate cap?...He was the first Black cartoonist to produce a nationally distributed comic strip..."
The San Francisco Chronicle published this profile in conjunction with a retrospective of Turner's work ("...a jazz fanatic who works at night listening to the music of Dizzy Gillespie -- model for Wee Pal hipster Diz -- Duke Ellington, and Jimmie Lunceford."). Below is a 2009 Keith Knight tribute which refers to the same exhibition: