Guardians of the Galaxy writer and director James Gunn has already confirmed the next installment in the franchise will be the final adventure of the current lineup. Vol 3, was originally planned for a release this year before the setbacks due to some controversy regarding Gunn, which meant he was dropped from the project. Gunn was eventually reinstated, thankfully, but it will be a while before we get to see the final chapter.
With the current Coronavirus pandemic, Gunn has had a lot of time on his hands and has been using social media to interact with fans and reveal details about the franchise. One of his latest reveals though is very exciting and will hopefully mean that we will get to see the final chapter sooner rather than later.
With that being said, most of the Phase 4 release slots have been filled and it seems far more likely this will end up as a Phase 5 release. It is due for release in February 2023 but this date may change. Taika Waititi, writer of Thor: Love and Thunder stated the current delays are a good sign, as it allows him to polish off the film, I am sure Gunn is thinking the same.
Not much is known of the plot with most believing it will revolve around the team searching for the alternate timeline version of Gamora. Gunn has also recently revealed that there will be a death in the film, so we can only assume that this will be an emotional finale to the Guardians trilogy.