It looks like Call of Duty: Modern Warfare 2, which is rumoured to be releasing later this year, will be the final entry in the rebooted Modern Warfare series.
According to RalphsValve, a trusted industry insider, Call of Duty: Modern Warfare 2 intends to conclude the rebooted series that began in 2019.
When the three-year cycle came back around to Infinity Ward in 2019, rumours soon began circulating that the developers would be continuing the Modern Warfare series with a fourth entry.
Infinity Ward then went on to work on other Call of Duty projects such as Call of Duty: Ghosts and Call of Duty: Infinite Warfare.