This is an observational study with a prospective cohort design. This study enrolled patients with suspected hilar cholangiocarcinoma on imaging. This study aims to evaluate the histopathological diagnostic efficacy of endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/B) and endoscopic retrograde cholangiopancreatography (ERCP) with or without peroral cholangioscopy targeted biopsy (POCS-TB) in patients with suspected hilar cholangiocarcinoma. In addition, the incidence of complications was compared between the EUS-FNA/B and ERCP with or without POCS-TB. The impact of the histopathological diagnosis on survival outcomes in patients with suspected hilar cholangiocarcinoma was evaluated.