Chrome apps are the ones installed in Chrome; they work similarly to apps launched on desktops. However, they are not widely adopted. The Verge reported in August 2016 that around "1 percent of users on Windows, Mac, and Linux actively use Chrome packaged apps." It was in August of 2016 when plans to wind down support for the platform were first announced.
In January, Google announced the suspension of support for Chrome apps on Windows, Mac, and Linux. The deadline was supposedly June 2020 deadline. Now, Google says Chrome apps will continue to work on those platforms until June 2021.
According to The Verge, organizations may extend support for Chrome apps for an extra year. Hence, the apps could work through June 2022.
For Chrome OS users, Google will end support for Chrome apps in June 2022, not in 2021. Nevertheless, support for Chrome apps will halt on all platforms by June 2022.
Do not, however, that Chrome extensions will continue to work. Google recommends Chrome extensions as alternatives for developers who must wean themselves from Chrome apps. Extensions offer similar functionality as the apps within the Chrome browser.