Specifically, we explore (i) the differences of T cells infiltrating tumor regions compared to when located adjacent to the tumor, (ii) the molecular profile of infiltrating CD57− and CD57+ subsets of T cells, which represent early and late differentiation stages, and (iii) the connection between the degree of T-cell infiltration (T-cell rich or T-cell sparse) in MCL and molecular features of tumor and T cells (Figure 1A). Here, B3GAT1 is linked to mantle cell lymphoma.