Attack on Titan would bring its season 3 to a closure with an episode 22 releasing this July.
Attack on Titan is a Japanese fantasy anime television series by Hajime Isayama, adapted from the Japanese manga of the same name. The 1st season of which premiered in 2013 in Japan. The story of the show is about the adventures of Eren Yeager (protagonist) living in a world where humanity lives inside cities surrounded by enormous walls to protect them from the Titans, which are gigantic humanoid creatures that destroy and kill humans apparently without any specific reasons.

Season 3 that is currently being aired is considered to be one of the most essential and thrilling seasons of this series. The secrets of the Titans and the outside world is being revealed episode by episode leading the audience towards a more exciting season 4.
A brief synopsis of the finale episode of the season 3 was revealed by Attack on Fans over a tweet-
Episode 59's summary is revealed! 🔥🔥🔥
"The truth outside the walls and the identity of the Titans were revealed. Historia and army officers who knew it made a decision. And Eren was thinking about what is outside the walls…"https://t.co/vakCbcBU5h pic.twitter.com/AuYSEsjuFM
— Attack On Fans (@AttackOnFans) June 26, 2019
English version-dubbed:
The series will be available with English subtitles within a few hours of the release. The English dubbed version of the show releases roughly after a month from the original Japanese version. However, if the episodes of the English version are being released at the same pace as they are released now, then the episode 59, i.e., the 22nd and the finale episode of the season 3 of the show is expected to release somewhere near 27th July while the Japanese version would end the season 3 on 1st of July.
There has been no official news regarding the season 4 of the series but looking at the events of the current season people are expecting a more adventurous season 4 intended of having a close encounter or maybe a war between the humans and the Titans.