For example, after TIL infusion, low-dose IL-2 may be used, or even a new type of IL- 2, including IL-2 mutein substitutions at key sites or IL-2 analogs, which have been shown to reduce high-affinity IL-2 receptor binding,58 thereby reducing IL-2 toxic side effects, especially blood vessel expansion and pulmonary edema, and will not activate and expand CD4+Foxp3+ Tregs.59 Here, IL2 is linked to pulmonary edema.