There are already plans for Phase 5, which is hoped/expected to include the arrival of the X-Men and Fantastic Four in the MCU, plus Blade, sequels for Black Panther and Captain Marvel, and Guardians of the Galaxy 3. There were three MCU movies in 2019 but only two coming in 2020, and then four in 2021. I’m not sure if four will be he new normal, but Marvel fans seem down for that.
Article source: https://www.cinemablend.com/news/2481663/the-mcu-infinity-saga-box-set-looks-awesome-and-costs-everything