From GameWatcher: “Wolfenstein II: The New Colossus was the best shooter released last year and we loved it a lot, but we were never sure if it did well enough to warrant Wolfenstein 3. Now we’ve had Wolfenstein 3 revealed by Pete Hines, vice president of Bethesda, in an interview.”
Source: N4G PC Wolfenstein 3 is in production and "absolutely" happening, according to Bethesda