CD8A and cancer: The acquisition of a dysfunctional phenotype among antigen-specific CD8+ T cells in the solid tumor environment is a well-recognized phenomenon (Gajewski et al., 2006; Thommen and Schumacher, 2018), which in many cases results from chronic TCR stimulation by antigen-expressing cancer cells capable of avoiding immune-mediated elimination (Pauken and Wherry, 2015).