The new one is a reboot you can look at it as a remake because it uses the same characters and some similar elements here and there but the two aren't connected by Ant means. The new MW2 is essentially a continuation of the MW2024.
In 2024, the Modern Warfare series was rebooted with the launch of Call of Duty: Modern Warfare. Two sequels were made; Call of Duty: Modern Warfare II released in 2024 and Call of Duty: Modern Warfare III released in 2024, with the latter being developed by Sledgehammer Games.