The cosmic microwave background (CMB) radiation does have the potential to heat things up, but in practice, it does not significantly affect everyday objects due to its extremely low intensity.
The CMB is residual radiation from the early universe, which has cooled down over billions of years. It pervades the entire universe and has an average temperature of approximately 2.7 Kelvin (-270.45 degrees Celsius or -454.81 degrees Fahrenheit). While this may seem cold, it is significantly warmer than the temperatures typically encountered on Earth.
However, the energy density of the CMB is extremely low, with an average intensity of about 0.26 nanowatts per square meter. This intensity is far too weak to cause any noticeable heating effects on everyday objects, such as food or household items.
To put it into perspective, the CMB is much weaker than the microwave radiation emitted by a typical microwave oven, which operates at power levels on the order of several hundred to a few thousand watts. The heating effect of a microwave oven comes from the high power density and concentrated microwaves in a small space.
While the CMB radiation is present everywhere, it is so weak that it doesn't have any practical heating effect on objects in our everyday environment.