Is a pediatric hematology/oncology a type of surgeon or a nurse?

Neither: It's not a surgeon; it's a pediatrician specialized in the diagnosis and treatment of childhood cancers and blood diseases.

Neither: Hematology is the study of diseases affecting the hematopoietic system, for example cancers. Hemoglobinopathies, clotting disorders etc... Oncology specializes in cancer treatment and management. A doctor specializing in pediatric hematology/oncology oversees the treatment and diagnosis of cancer of the blood and some genetic diseases. Reference: http://en.Wikipedia.Org/wiki/hematology.

Not a surgeon: Pediatric hematologist-oncologists are doctors that treat children with blood disorders and cancer. They are not surgeons, although they do perform minor surgeries (lumbar punctures and bone marrow examinations mostly). There are also nurses that are specialists in pediatric hematology/oncology and treat children in the hospital and as outpatients under the direction of the doctor.