Abstract: The subject matter disclosed herein is generally directed to CD8+ tumor infiltrating lymphocytes comprising gene signatures associated with response to immunotherapy treatment. Moreover, the subject matter disclosed herein is generally directed to methods and compositions for use of the gene signatures. Specifically, disclosed herein are gene signatures associated with response to checkpoint blockade therapy and immune cell subtypes characterized by said gene signatures. Further disclosed are methods of using said gene signatures and immune cell subtypes. Further disclosed are pharmaceutical compositions comprising populations of CD8+ TILs enriched for a specific subtype.