The integration of Salesforce Service Cloud with Unix/Linux multi-cloud environments is critical for enterprises seeking to modernize CRM operations while maintaining legacy system reliability. This review examines strategies for connecting RESTful APIs and SOAP services with Unix/Linux backends, emphasizing secure data exchange, workflow orchestration, and operational resilience. Core topics include API integration best practices, middleware orchestration, high availability, predictive monitoring, and compliance with regulations such as GDPR, HIPAA, SOX, and PCI DSS. Industry case studies from financial services and healthcare illustrate practical applications and benefits, highlighting faster response times, enhanced customer engagement, and reduced operational risks. Emerging trends, including API-first strategies, microservices, containerized deployments, and AI-driven observability, are analyzed to provide a roadmap for future-ready hybrid architectures. The review concludes that combining cloud-based CRM automation with robust Unix/Linux integration enables enterprises to achieve efficient, secure, and scalable operations while preserving compliance and data integrity.