I am running the following code

cmake_minimum_required(VERSION 3.14)

project(LocksProject)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(lock_example example.cpp)

example.cpp

#include <thread>
#include <iostream>

int main() {
    std::jthread {[] {std::cout << "Hi" << std::endl;}};
}

cmake prints

-- The C compiler identification is AppleClang 13.0.0.13000027
-- The CXX compiler identification is AppleClang 13.0.0.13000027

make prints an error:

error: no member named ‘jthread’ in namespace ‘std’
std::jthread {[] {std::cout << “Hi” << std::endl;}};