Nephrologist pulled lisinopril from my regimen, but a new internal med put me back on it. I have CKD stage 4, GFR 22. If it helps kidney why remove?

Stage 4 ckd. Lisinopril at GFR 22 can easily reduce kidney function further and elevate potassium. Your nephrologist is following concensus caution for you.
It depends. Lisinopril helps kidneys live longer. However, if it slows your kidneys significantly or brings your potassium up, you need to stop it. I presume that your internist did not know that your nephrologist stopped it. Since you have an advanced kidney disease, i would re discuss it with the nephrologist. Would not wait long!