Additionally, PD-L1 can be expressed by various cell types within the tumour microenvironment, complicating the scoring and interpretation process [22]; therefore, it has been recommended that PD-L1 expression should not be used to guide the choice of combined (anti-CTLA-4 and anti-PD-1) ICI therapy for patients [23]. The gene discussed is CTLA4; the disease is neoplasm.