Just add the following two settings via File | Preferences | Settings:

    "terminal.integrated.shell.windows": "cmd.exe",
    "terminal.integrated.shellArgs.windows": [
        "/k", "C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\Common7\\Tools\\VsDevCmd.bat"
    "terminal.integrated.automationShell.windows": null,

Also, adjust the VS install path to your version/edition of Visual Studio.

NOTE: The last line resets the settings for automation shells (i.e. running tasks), so that we don’t interfere with them.

You may also find these two settings useful, if you want the same cursor style and blinking in the terminal as in the editor:

    "terminal.integrated.cursorBlinking": true,
    "terminal.integrated.cursorStyle": "line",

Finally, the default Ctrl+K keybinding to clear the terminal window won’t work in cmd.exe, just rendering a useless ^K, so I also set it to Ctrl+Shift+K instead via the File | Preferences | Keyboard Shortcuts menu by adding the following:

        "key": "ctrl+shift+k",
        "command": "workbench.action.terminal.clear",
        "when": "terminalFocus"