H1-B is a valid temporary non-immigrant visa i.e. if an individual loses the validity then he or she goes out of valid non-immigrant status and eventually gets into legal complications. In the case of H1-B if an individual is fired then he or she has no sponsorship to be able to continue to work in United States and if unable to find a new employer who’s willing to transfer the H1_B then the respective individual had to leave the country or transfer to other available visa categories such as F1 student visa to be able to stay in USA.
It’s imperative to leave the country in a reasonable time (Consult Immigration attorneys) so it’s easier for the H1-B employee to get back in when they found a suitable employer in future. If continued to stay without sponsorship, then the respective H1-B employee risks accruing illegal presence in United States and eventually will end up de-barred from USA simply out of ignorance. This is an awfully bad situation since even if the individual gets back home the probability of a multi-national company abroad hiring someone who is de-barred from US is slim. Therefore, it is very critical to stay on a “Valid” status and understand what it take to keep the status valid, and consequences of failing to do so