If you are confused with what these two items are, you should know that CFM and SCFM are known to be air compressors. SCFM is normally measured under controlled environments. The SCFM will also measure pressure, relative humidity, and temperature.
The things that will be measured by the CFM are different. This would measure the volume rate of the flow system. This can help gain more details about temperature and pressure. If you would check the rating of the CFM and the SCFM, you will notice that the CFM will always have a lower rating as compared to the SCFM.
To choose the right air compressor, make sure that you will know what you would need to use it for. This will make a lot of difference to your decision.