In the modern workplace, silos will emerge when you or your co-workers get territorial about your role, your resources, or your department. Silos may provide you a feeling of control or calm your fears of becoming dispensable.
In reality, jobs are defined, departments, and hierarchies are set up for administrative convenience only. It improves coordination when duplication is reduced.
However, for many critical problems, it does not matter who solves the problem. A drop in revenue, or profit, a competitive threat, talent attrition, political turmoil, are examples of problems that are not the domain of a single department. Multiple perspectives are required to even understand the problem. Collaboration and partnerships are required to define and implement the solution.
To tear down the silos, the first step is to educate your co-workers about the nature of the problem that is being solved, and show that cross functional participation is required. If anyone shows initiative or interest to solve the problem, provide them the resources, but insist on a transparent governance model.