In Visual Studio Code’s integrated terminal the default ctrl+f key binding opens the find/search dialogue. As a fish user, I need ctrl+f to perform command history completion. The default behaviour can be disabled by entering the following into your settings.json file. See: Terminal Basics – Find.
"terminal.integrated.commandsToSkipShell": [ // Disable terminal's default ctrl+f // keybind for fish shell "-workbench.action.terminal.focusFind" ]