Invincible co-creator Robert Kirkman revealed that Season 4 will introduce a brand new story not seen in the comics.
Season 3 adapted the comics run closely, but the post-credits scene featured a returning character, leading to a new story in Season 4.
I wrote the fourth episode.
Robert Kirkman confirmed that the original story will take place during Season 4's fourth episode, which he directly wrote.
Author's summary: Invincible Season 4 introduces new story.