The clonal transmissible cancers known as Tasmanian devil facial tumours (DFTs) represent an immunological enigma as they are simultaneously cancer, infectious agents, and allografts. The two devil facial tumours (DFT1, DFT2) arose independently and have undergone sustained natural transmission in the wild since at least 1996 and 2014, respectively. The transmissible cancers evade host immunity despite genetic mismatches at MHC-I loci and accumulate mutations in tumour cells. We have developed panel of devil-specific monoclonal antibodies and recombinant proteins to understand immune evasion and inform vaccine development. We used our Fluorescent Adaptable Simple Theranostic (FAST) protein system to confirm seven evolutionarily-conserved receptor-ligand interactions among twelve checkpoint proteins. We have also identified that CD200 is highly expressed on DFT cells to allow identification of DFT cells spiked into devil whole blood in the lab. We are moving towards using additional markers to attempt to identify metastatic DFT cells in blood collected in the field. We have also documented that devil checkpoint proteins can capture other checkpoint proteins from neighboring cells through trogocytosis and transendocytosis, as observed previously for placental mammals. Our analysis suggests that protein interactions and intercellular protein transfer pathways are conserved across species in many cases. For example, the receptor-binding domain in the potent checkpoint protein CTLA4 is 100% conserved across most mammals and birds. Finally, our expanding immunology toolbox will be used to document the devil immune response to an adenoviral vaccine we in development.