https://www.pcgamer.com/wolfenstein-3-is-absolutely-being-made/

The Wolfenstein series numbering scheme is a little messy. Castle Wolfenstein was the first, but the FPS series as we know it started 25 years ago with Wolfenstein 3D. Sequels and reboots led to Wolfenstein—just Wolfenstein—in 2009, after which Bethesda took over and gave us Wolfenstein: The New Order and then Wolfenstein: The Old Blood, neither of which were Wolfenstein 2, which didn't come along until last year. This year, Bethesda revealed Wolfenstein: Youngblood at E3, which in keeping with that complicated tradition is not Wolfenstein 3 but rather a standalone spin-off. 

A proper Wolfenstein 3 is on the way, however, although you probably don't want to start holding your breath waiting for it just yet. "Absolutely we’re making a Wolfenstein 3," Pete Hines, Bethesda's vice president of PR and marketing, said in an interview with Metro. "They said on stage [at E3] that they’re taking a break from the larger story to do this thing. But we all have to see how that ends."