Announced in Nintendo's latest financial results (reported by VGC), they're planning to launch their next system this decade. The Japanese company is currently considering its options, so this unknown console isn't expected to launch for at least several years.
Nintendo's Preparing Their Next Console, Just Don't Expect It Anytime Soon
Nintendo labels the console as "Integrated Hardware-Software Next gaming system", with "20XX" listed as the launch date. VGC states that the company is discussing its next steps, with nothing finalised at the moment.
Nintendo reportedly said it is still going through internal discussions on the hardware concept and launch timing, suggesting many significant details have yet to be finalised.
Constant rumours have suggested the existence of a Switch Pro. A teardown of the OLED Switch revealed the presence of 4K HDMI peripherals, with capabilities of reaching 60 FPS. Another report emerged last month claiming that Nintendo is aiming for a 2022/2023 launch for their handheld's next iteration, which may have exclusive games.
Considering Nintendo's only just released the OLED Model, it's highly unlikely they'd confirm a new system anytime soon. For now, we'll have to wait and see.