What do systematic reviews say?

Pembrolizumab vs chemotherapy alone

Pembrolizumab may leads to lower serious adverse events (irrespective of attribution to treatment) compared with chemotherapy (low certainty).

• Pembrolizumab monotherapy versus chemotherapy for treatment of advanced urothelial carcinoma with disease progression… 2018 · Cochrane Headline outcomes only
  RR 0.83 [0.72, 0.97]
  1 study · 521 participants
  Low