Host adaptations in response to the DFTD epidemic have been diverse, including developing anti‐DFTD antibodies resulting in tumour regressions (Margres et al., 2020; Pye, Hamede, et al., 2016), variation in susceptibility to infection due to differences in expression levels of natural (IgM) versus specific (IgG) antibodies (Ujvari et al., 2016), sex‐biased differences in tolerance to infection (Ruiz‐Aravena et al., 1891) and changes in allele frequencies in genomic regions associated with cancer and immune function (Epstein et al., 2016; Fraik et al., 2020; Stahlke et al., 2021). Here, CD40LG is linked to infection.