The tissue-resident adaptive NKs were the only subset (out of six) that demonstrated consistent, robust associations with improved survival across different primary, therapy-naïve and metastatic solid tumours, and in response to checkpoint blockade. Notably, elevated infiltration of these NKs was more prognostic than high tumour mutational burden in certain types treated with checkpoint blockade. Additionally, these NKs were strongly correlated to the infiltration of CD8+ T-cells and B-cells in tumours. Interestingly, paired pre- and post- checkpoint blockade treated tumours revealed expansion of cytotoxic tissue-resident adaptive NKs after treatment.