"Merchant of Death" is a claim made by prosecutors and people trying to sell movies, books, and products based on him.
His last deal was over 13 years ago and he has been a convenient fall guy for governments and organizations deploring the arms trade they secretly supply. If he was not in this prisoner swap he was scheduled to be released in 2029. He used multiple companies to smuggle weapons, which can be a lucrative career if you avoid being caught or killed.
His contacts are over 13 years old, and claims he is going to be immediately employed by Russia to supply them with weapons and ammo look like desperate attempts to smear Biden.