CTLA4 and head and neck cancer: However, the study population were quite heterogeneous in cancer types (six genitourinary cancer, three melanoma, three merkel cell carcinoma, three head and neck cancer), ICI regimen (90% anti-PD-1/PD-L1, 5% anti-CTLA-4 and 5% combined anti-PD-1/CTLA-4), and dialysis modality (79% hemodialysis, 21% peritoneal dialysis), which limited to achieve a definite conclusion (32).