The End of Support Calendar shows Microsoft Operating Systems end of support dates, whether they are the end of mainstream support that updates features and cosmetic changes, or extended support, which ends security fixes and all Microsoft technical support other than old web pages.
Windows 10, version 20H2, released October 20th, 2020, was named using the new 'H2' label to indicate the second half of the year. It will reach the end of life, and no longer receive security updates, as of May 10th, 2022.
In all Windows 10 Semi Annual Channel editions, support for the Internet Explorer 11 desktop application will end June 15th of 2022.
If your other software relies on Internet Explorer, investigate using "Internet Explorer mode in Microsoft Edge", which Microsoft has said will be supported, on supported operating systems, through at least 2029.
Windows 10, version 21H1, named for the release date of First Half of 2021, will reach end-of-life, on December 13, 2022, and will no longer receive security patches after that date.