CD44 and infection: To analyze the transcriptional-metabolic programs along the developmental trajectories of exhausted T cells, we performed single-cell (sc) RNA sequencing of CD44+ PD-1hi CD8+ T cells isolated from chronically infected wild-type (WT) mice after infection with the clone 13 strain of lymphocytic choriomeningitis virus (LCMVCL13) (Supplementary Fig. 1a).