It looks like it will remain largely a technology demonstrator for the next 10 years as its intended engines are developed:

The Kremlin’s new state armament plan, which will run from 2018-2027, will continue modernization of the Russian Aerospace Forces. However, while Russia will continue to buy modern combat aircraft such as the Sukhoi Su-35S Flanker-E air superiority fighter and the Su-34 Fullback bomber, Moscow is not likely to make large purchases of the fifth-generation Su-57 PAK-FA stealth fighter until after 2027.

“The Su-57 is not expected to enter into serial production until upgraded engines are ready, which is unlikely to happen until 2027,” Center for Naval Analyses senior research scientist Dmitry Gorenburg wrote in a new PONARS Policy Memo. “Over the next eight years, Russia will continue to purchase small numbers of these planes for testing.”

………

During the coming years, the Russian air force is likely to focus on addressing support aircraft such strategic airlifters and intelligence, surveillance and reconnaissance planes. Moreover, the Russians will also have to address persistent problem with their aerial refueling capabilities.

“Transport and refueling aircraft, long an area of weakness for the Russian air force, will be one area of focus,” Gorenburg wrote. “Serial production of the long-troubled Ilyushin Il-76-MD90A is expected to start in 2019, and the Russian military is expecting to receive 10-12 such aircraft per year thereafter. A light transport aircraft is under development, with prototypes expected to be completed in 2024.”

Obviously, this is not an official announcement by Russia, but it makes sense.

Refueling, transport, and AEW are significant weaknesses in the current Russian aviation forces, and their fighter force is largely recapitalized, so it’s a case of focusing resources on the most obvious weaknesses.