The purpose of this study is to evaluate efficacy of erdafitinib versus chemotherapy or pembrolizumab in participants with advanced urothelial cancer harboring selected fibroblast growth factor receptor (FGFR) aberrations who have progressed after 1 or 2 prior treatments, at least 1 of which includes an anti-programmed death ligand 1(PD-\[L\]1) agent (cohort 1) or 1 prior treatment not containing an anti-PD-(L) 1 agent (cohort 2).