If a person has any kind of cancer cells in body could it b diagnosed wth CBC blood test.

No. A CBC looks at blood cells; white, red, and platelets, shapes and sizes. A CBC is only suggestive and not even diagnostic for blood (hematologic) malignacies.
Cancer and Blood. Nope. Probably not in any way. There are a thousand different kinds of cancer. Are you aware of this?
Not really but. Cancer cells in body can not be diagnosed by CBC blood test.But some cancers can be suspected based on CBC test, for example multiple myeloma, leukemia, or lymphomas.