How did the Marvel Transformers comic series conclude, and what was its lasting legacy?

The US Marvel Transformers comic series concluded with issue #80 in 1991, titled 'End of the Road!'. The final arc saw Unicron's arrival, Optimus Prime's ultimate sacrifice to stop him, and the apparent end of the Autobot-Decepticon war with the Decepticons being defeated and Optimus Prime merging with the Matrix. The UK series continued for a while longer, wrapping up with its own conclusion. The lasting legacy of Marvel's run is immense; it established much of the foundational lore, characterizations, and storytelling tropes that would define Transformers for decades, influencing the Beast Wars animated series, the Dreamwave and IDW comic continuities, and even the live-action films.