  SS433 is an X-ray binary emitting persistent relativistic double sided jets
that expand into the surrounding W50 radio nebula. The SS433/W50 system is then
an excellent laboratory for studying relativistic jet interaction with the
surrounding interstellar medium. In this context, part of W50 nebula has been
mapped with ISOCAM at 15 micron, where the large scale X-ray jets are observed.
I will show the results, particularly on the W50 western lobe, on two emitting
regions detected in IR with IRAS, and observed in millimeter wavelength
(CO(1-0) transition). It is uncertain whether these regions are due to heated
dust by either young stars or the relativistic jet, or to synchrotron emission
from shock re-acceleration regions as in some extragalactic jets from AGN. In
this latter case, INTEGRAL might detect soft gamma-ray emission.
