With the rapid increase in the use of nanotechnology and immunotherapy for cancer management in the recent past, there are great implications for using nanotechnology in immuno-oncology. However, to deliver clinical success, the scientific and clinical rationale must be critically evaluated when applying nanotechnology to immuno-oncology challenges. This opinion article distinguishes between designing nanotherapeutics for immunotherapy and the past focus on the placement of chemotherapy agents in nanoparticles. We believe the integration of nanotechnology with cancer immunotherapy for nano-immunotherapeutics provides unique opportunities for both fields, paving the way for entirely new therapeutic paradigms. As a particular focus in our article, we envision the necessities and challenges of nanotechnology in the development of in situ cancer vaccines, immune checkpoint inhibitors, adoptive cell transfer, and bispecific antibody therapy.