According to the latest update to the M.Zuiko lens roadmap from Olympus, there are four lenses on the horizon for 2020, including the highly anticipated 150-400mm F4.5 TC1.25x (pictured below) which received an earlier development announcement.
The 150-400mm lens features a built-in 1.25x teleconverter and covers a focal length range of 300-1000mm (35mm equivalent). With the MC-20 2.0x extender, this makes handheld super telephoto shooting theoretically possible at 2000mm (35mm equivalent).
- M.Zuiko Digital ED 150- 400mm F4.5 TC1.25x IS PRO
- ED 12-45mm F4.0 PRO
- ED 100-400mm F5.0-6.3 IS
- “An additional PRO telephoto zoom lens of an unspecified focal length”
As you can see from the roadmap, aside from what Olympus has mentioned there are also slots for a Wide Zoom PRO lens, a Bright Prime PRO lens and another Telephoto Zoom PRO lens. Given that the previous lenses in the list above were called out specifically for a 2020 release, I’d imagine that these other vague mentions are lenses that are earmarked for 2021 and beyond.
You can find lens roadmaps from the other camera manufacturers here.