Figure 1. Clinical scenarios of primary, adaptive and acquired resistance to immunotherapy.

A) Patient’s tumor is resistant to immunotherapy with no active immune response. B) Patient’s tumor is resistant to immunotherapy; active anti-tumor immune response but turned off by checkpoints or other adaptive resistance mechanisms. C) Patient has an initial response to immunotherapy but later progressed – heterogeneous population and selection of resistant clones that were present before treatment started. D) Patient has an initial response to immunotherapy but later progressed, true acquired resistance during the immunotherapy.