CD8A and neoplasm: Moreover, the two response parameters derived from the model, Λ and μ, represent abstract terms, which may not precisely model intratumoral CD8+ lymphocyte infiltration and tumor cell PD-L1 staining and potentially can be modified by relevant determinants, such as tumor mutational burden (Goodman et al., 2017) or the human microbiome of the gut (Gopalakrishnan et al., 2018).