Hybrid Project Management is a project management approach that combines Predictive (Waterfall) and Agile methods within the same project to get the best of both worlds.
There are multiples ways of doing this;
Plan and execute the project following predictive project management and at the same time include agile ceremonies like planning meetings, daily standup meetings, frequent reviews, retrospectives etc...
Some modules where requirements are stable, follow waterfall and for those modules where requirements are evolving follow agile and integrate the output and pre-defined integration points.