IL2 and neoplasm: Evaluation of cytokine signaling with a radiolabeled transforming growth factor (TGF)-β inhibitor, and SPECT imaging of tumor-infiltrating lymphocytes (with 99mTc-labeled interleukin-2), regulatory T cells, and tumor-associated macrophages, are some of the developments beyond PD-(L)1 imaging that could contribute to improved assessment of response to ICI therapy and subsequent clinical management (42, 57).