  SS433 is a jet emitting X-ray binary surrounded by the W50 radio nebula. The
SS433/W50 system is an excellent laboratory for studying relativistic jet
interaction with the surrounding interstellar medium. In this context, part of
the W50 nebula has been mapped with ISOCAM at 15 micron. I will show the
results particularly on the W50 west lobe, and on 2 emitting zones detected
with IRAS who have also been observed in millimetre wavelength (CO(1-0)
transition), and for one of them by spectroscopy with ISOLWS and ISOSWS between
2 and 200 micron.
