Title: Learning Dynamic Query Combinations for Transformer-based Object Detection and Segmentation. Abstract: Transformer-based detection and segmentation methods use a list of learned detection queries to retrieve information from the transformer network and learn to predict the location and category of one specific object from each query. We empirically find that random convex combinations of the learned queries are still good queries for the corresponding models. We then propose to learn a convex combination with dynamic coefficients based on the high-level semantics of the image. The generated dynamic queries better capture the prior of object locations and categories in the different images. Equipped with our dynamic queries, a wide range of DETR-based models achieve consistent and superior performance across multiple tasks (object detection, instance segmentation, panoptic segmentation) and on different benchmarks (MS COCO, CityScapes, YoutubeVIS).