Recent clinical trials have demonstrated that antiâPDâ1 blocking antibodies showed remarkable clinical efficacy in a subset of nonâsmall cell lung cancer (NSCLC) patients. Clinical trials usually exclude patients with renal dysfunction who are receiving hemodialysis (HD). Therefore, it is unclear whether these patients can be safely and effectively treated with pembrolizumab. Here, we present a nonâsmall cell lung cancer patient on HD who achieved complete remission after one dose of pembrolizumab without severe adverse events. We assessed pembrolizumab binding to peripheral blood T cells in this patient using a method that we recently developed. This is the first report to visualize pembrolizumab binding to T cells in a patient on HD during and after pembrolizumab treatment. The pharmacokinetics of pembrolizumab in this case were similar to those in patients with normal renal function, suggesting that severe renal dysfunction has little influence on the metabolism of pembrolizumab, and is not a contraindication for antiâPDâ1 treatment. Immune checkpoint inhibitors, including pembrolizumab, may be a vital therapeutic option for lung cancer patients on HD.