The orchestration of applications across the IoT–Edge–Cloud (CEI) continuum is a fundamental enabler of today’s internet services andglobal digitization, supporting adaptive resource management and performance optimization in heterogeneous environments. Withinthis orchestration process, scheduling and placement constitute critical decision mechanisms that determine how computational tasksand services are allocated across federated infrastructures.This paper presents a survey of scheduling approaches designed to support application orchestration across the continuum. Througha systematic analysis of 63 peer-reviewed studies published between 2019 and 2025, the survey consolidates a fragmented bodyof knowledge encompassing diverse objectives, architectural paradigms, and evaluation practices. A comprehensive taxonomy isproposed to structure existing work along key analytical dimensions, including scheduling objectives, problem scale, architecturalmodels, and evaluation methodologies.The analysis highlights the research gaps and emerging challenges, contributes to an integrated perspective on the status offederated orchestration and scheduling strategies. This study reveals that scheduling research in CEI continuum remains focusedon single-cluster and small-scale evaluations, as more than 70% of the reviewed articles focused on single-cluster environments andabout 79% of the studies evaluated their methods in small-scale environments. The exploration of fully decentralized multi-clusterarchitectures, and using large scale evaluation are still limited.