I should add to Gurpreet's response that capability to retrieve streaming market data is on the roadmap for Eikon Data API. It is expected to be delivered this year. The capability to subscribe to streaming news headlines with filters however is not currently on the roadmap. It's very likely that using streaming market data capability you will be able to subscribe to RIC NFCP_UBMS, which provides streaming news headlines without any filtering. The filtering you would then need to implement yourself based on the payload of news headlines updates. Eikon COM and .NET APIs can be used to subscribe to NFCP_UBMS today.
In Eikon Data API executing get_news_headlines method is the only option to refresh the headlines. If you do it once every few seconds, that's probably OK. If you have several filters that need to be refreshed periodically you should be aware that the API proxy limits the frequency of requests to the max of 5 per second. Additional limits on data consumption may be introduced in the future.

Hi @p.volgger, Eikon Data API does not have streaming capability. The newly released websocket API complements the Eikon API, but requires TREP infrastructure to get data.

There are other streaming market data API's like EMA, which work with Thomson Reuters Enterprise Platform (TREP), and can be used to subscribe to MRN news feed, which seem better suited to your requirement.