Conceptual scheme, not to scale. Left panel: Microquasar (t <  t₀). The stellar-mass BH and the star are in the core. The backward shock at the end of the jets accelerates particles to relativistic energies. An overpressured cocoon evolves with the jets and envelops the entire system. Right panel: Microquasar remnant (t >  t₀). The central engine shuts down, and an MQR forms. Cosmic rays distributed within the survivor cocoon interact with a fragment of a molecular cloud that enters the MQR, illuminating it.