The nutritional and energetic interplay between tumor cells and intratumoral immune cells leads to metabolic competition.[70] Arginine concentration plays a critical role in the survival capacity and antitumor immunity of cytotoxic CD8+ T cells.[47, 49] Our study illustrates the competition for arginine between SLC3A2‐proficient PTCL cells and CD8+ T cells. Here, CD8A is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.