After the series ended, the showrunner announced that a spin-off was being negotiated. It was to be a prequel, the first episode of which had been incorporated into the seventh season.
It has now been over a year since The CW aired the last episode of The 100 and the spin-off project has unfortunately not moved forward. It seems that the American channel has decided not to give a favorable response.
The prequel will therefore never see the light of day on The CW, but it is not completely over since a streaming platform could decide to produce it. One thinks in particular of HBOMax which originally was to participate in the development of the prequel.
Netflix could also enter the race and try to appropriate the rights to the series to be able to obtain the exclusivity of this spin-off which would make it gain many subscribers. The company with the red logo has already succeeded in this kind of operation in the past, notably with the Vikings series, the spin-off of which will soon be appearing in its catalog.
Jason Rothenberg (showrunner of The 100) is certainly still going and will not give up the world of fiction so easily. Hopefully, he will find the funding to stage this long-awaited prequel by fans!