In this study, we developed and characterized CSF1 CRISPR-Cas9 knockouts in the 4T1 mammary and MC38 murine colon carcinoma cell lines to further understand the effects of CSF1 depletion in vitro and in vivo and determined its impact in tumor growth, tumor microenvironment, and epitope spreading. This evidence concerns the gene CSF1 and colon carcinoma.