High-risk M3 tumours not only contain more infiltrating lymphocytes and macrophages, but also express higher levels of immune checkpoint inhibitors: we show that LAG3 is co-expressed with other immune checkpoints (PD-1, CTLA-4, and IDO-1), suggesting that the combination of anti-checkpoint therapies might be more appropriate in UM than single anti-checkpoint antibodies, as others also find this appropriate in other diseases such as cutaneous melanoma [27]. The gene discussed is IDO1; the disease is cutaneous melanoma.