Attack on Titan (or Shingeki no Kyojin in Japanese) season 3 aired its final episode for season 3 (streamed here in the USA). Shortly after the episode aired on Japanese TV, it was announced that season 4 would start in the Fall of 2020, and will be the show’s final season.
Here is the very short tease (in Japanese):
Attack on Titan season 4 will once again air on NHK in Japan next Fall. No word yet on whether it will air in the west localized, but hopefully it will follow previous trends and also be streamed here within a day of its airing in Japan.