Furthermore, Cho et al. studied 20 melanoma patients treated with different ICIs (anti-PD-1 and anti-CTLA-4) with PET/CT at 3–4 weeks into therapy and found that a combination of changes in lesional dimensions along with changes in [18F]FDG uptake is a more accurate predictor of eventual response than each of these parameters alone. Here, PDCD1 is linked to melanoma.