"Naruto" Author Hints at New Series

During the promotion for the opening of Boruto, Naruto author Masashi Kishimoto mentioned that he Boruto and the Naruto: The Seventh Hokage and the Scarlet Spring manga. As he moves past the summer's projects, he's hinting at what's to come. 
was taking a break and long overdue honeymoon, but back last fall he suggested that he had more work in mind for after he wrapped up projects like

Kishimoto recently expressed interest in doing a sci-fi in the digital Shonen Jump Plus, which offers more freedom with page counts and publication dates than the print version.

“I’ve already decided what I’m doing for my next work,” Kishimoto replied. “While I was still doing Naruto, I thought about various things for material, and for the next one, I’m thinking I’m going to do science-fiction.”

“It hasn’t all been worked out, and I haven’t showed my editor yet, but I’ve already designed the characters.” 

“Since Naruto was a bigger hit than I could ever imagine,” Kishimoto said, “I’d like to aim for the next hit. I don’t know when I can announce the next manga, but because I plan on challenging myself to surpass Naruto, please wait for it.”