CD4 and pneumocystosis: Treatment with immunoglobulin, TMP/SMX, and prednisolone was initiated, and the patient's symptoms rapidly ameliorated.<h4>Conclusion</h4>The patient in the present case developed PJP despite a CD4+ T-cell count of >200/μL after CAR-T cell therapy, probably because of inadequate CD4+ T-cell activation caused by B-cell depletion after CAR-T cell therapy and repeated abnormal macrophage immune responses after CBT.