I have made it to Episode 5 of Deutschland 86.
They mention that every western intelligence in the world wants Martin. Why do they want him?
"Enemy" intelligence officers would be an asset to any intelligence agency, if they can be turned or made to talk (or, if not, reducing the enemy's capacity). Martin is deeply embedded within the HVA and DDR security apparatus, is a highly trained agent, knows a lot -- as part of the story, he's pivotal to many of the events that precipitated the end of the Cold War -- and has shown signs of defecting, or at least sympathy for Western values.