Single-cell initiatives (e.g., the Human Pancreas Analysis Program and spatial transcriptomics and proteomics) will help determine if these PD-L1+ residual beta cells, or the CPHN or Pdx1+-Glucagon+ cells observed in human T1D islets, behave like the resilient beta cells observed in NOD mice, and perhaps how they relate to proximity or composition of insulitis. Here, GCG is linked to type 1 diabetes mellitus.