Mesothelin-positive

Participants will have a sample of their white blood cells, called T cells, collected using a procedure called leukapheresis. The collected T cells will be sent to a laboratory at Memorial Sloan Kettering to be changed (modified) to become MSLN-targeted CAR T cells, the CAR T-cell therapy that participants will receive during the study. Participant study therapy will take about 3-4 weeks.