Ape Escape (not th be confused with the much more violent 2019 indie darling Ape Out) has been dormant since for nearly a decade, but with the 20th anniversary of the series upcoming in 2020, the developers at Sony's Japan Studio are teasing news on the series. They even say more will be shared very soon.
A tweet from a new official account this morning @pipotaru20th stated in Japanese and translated through Google, "happy New Year. This year also, exciting, wonderful! To send lots of important information!"

Subsequent tweets since then have promised more information and artwork as we approach the game's exact anniversary on June 24th. What the plans are for that anniversary are a mystery for now, though translating the account's bio promises more information soon.
"This is an official account to celebrate the 20th anniversary of the 'Monkey Catching Game' and 'Sarugetsch' series. We will deliver information about 'Sarugetchu” quickly.'
It could be that the Ape Escape series is getting its own revival in the same vein as those recently given to bygone PlayStation mascots Crash Bandicoot, Spyro the Dragon, and Sir Daniel Fortesque. None of the recent remakes of Crash, Spyro, and MediEvil games has done worse than "Fair" on OpenCritic, with October's MediEvil claiming the low spot with its 68 average, while the other two each scored in the low 80s, including the recent remake of Crash Team Racing which caps off the list with its high of 83.
If not a remake, perhaps a new game is coming soon too. For now, it's merely speculation, but the account's creation and its early activity imply more than just an account made to share the history of the series. It seems it has a future too.
Ape Escape debuted in 1999 on PlayStation and has since seen mainline sequels through 2005 on PS2, with further spin-offs coming to PSP and Vita, though only in Japan. The series has always been a bigger hit in Japan, so it remains to be whether Western markets will even participate in any potential new game release that may be in the works.
