I140 filing with new employer

Hello folks,

I have approved I140 with employer A. I moved to employer B and no GC process.

My question is- how long can I work with employer B without their GC sponsorship. In short, employer B will NEVER file GC.

Advise me on the options and best practices.

Thanks in advance.

Your current or any future employer can keep filing AC21 H1B extensions beyond the 6 years term using your approved I-140 assuming you left employer A after 180 days of I-140 approval.
However you can’t file for adjustment of status (I-485) when your priority date becomes current in future unless employer A still has the GC job offer for you and never withdraw the I-140.
I-140 is employer specific so lets say if you were working for your current employer and your PD becomes current and assuming employer A no more have the GC job , you will need to have approved I-140 and GC job offer from your current employer to be able to file I-485.