Next, using a co-culture in vitro model using CTLs and ccRCC cell lines (Figures 3 and 4), we investigated the effects of several small molecule inhibitors targeting signaling pathways that are aberrantly regulated in sunitinib-resistant cell lines and that have been shown to affect the sensitivity of PD-1/PD-L1 therapeutic approaches in other nonclinical models [47–49]. This evidence concerns the gene CD274 and nonpapillary renal cell carcinoma.