Over a decade later, many audience members still need the Fringe ending explained in depth due to the show's complex nature. Created by J. J. Abrams, Alex Kurtzman and Roberto Orci, Fringe premiered in 2008 and originally utilized a largely episodic structure, with the "case of the week" format driving forward development between the core cast. Over time, however, Fringe became more serialized, increasingly delving into long-term mysteries and convoluted story arcs. By the time Fringe reached season 5, the episodic structure had all but vanished, replaced with one season-long struggle against the Observers.

https://screenrant.com/fringe-series-ending-explained-observers-timeline-white-tulip/