Integrating on-premises databases, cloud services (Azure, AWS, Google Cloud), and third-party APIs is a significant challenge for Power BI consulting. Data sources often have different structures, refresh frequencies, and authentication protocols, leading to inconsistency. Power BI’s DirectQuery and Import modes have limitations, causing refresh failures and slow reports. Consultants must optimize queries using Power Query transformations, Azure Data Factory for ETL processes, and dataflows for preprocessing. Handling API rate limits, real-time data synchronization, and ensuring consistent schema mapping is critical to delivering seamless reporting and analytics solutions for businesses.