The Czech government has signed the PESCO agreement, which (although it does not say openly) means creating an Euro-Army. The aim is to push NATO out, because in the Alliance everything must be decided by absolute consensus, but in the EU, Brussels decides. Once the Czech army will be subjected to the EU, there will be no national control but all orders will come from Brussels.
The main aim of a Permanent Structured Cooperation on security and defence (PESCO) is to increase Member States' effectiveness in addressing security challenges and advancing towards further integrating and strengthening defence cooperation within the EU framework. Member States' participation in PESCO is based on a voluntary principle. The EU Council will be responsible for the overall policy, and the decisions will be taken by the member states unanimously. https://eeas.europa.eu/headquarters/headquarters-homepage/34226/permanent-structured-cooperation-pesco-factsheet_en