This may be explained by several differences, including the mouse strain (BALB/c versus C57/BL6), cancer model (renal cell carcinoma versus melanoma and lung carcinoma models) and modalities of immunotherapy (anti-CTLA-4 combined with other immunostimulants versus anti-PD-1) (Murphy et al., 2018; Wang et al., 2019). This evidence concerns the gene CTLA4 and melanoma.