The USP7 inhibitor P5091 has shown an antitumor activity in several cancer systems, such as in colorectal carcinoma through the destabilization of β-catenin [37], in chronic lymphocytic leukemia by activation of the p53/p21 signaling axis [38], and in lung neuroendocrine tumors and prostate cancer [17, 21], in association with PARPi, through the destabilization of CCDC6 [12]. The gene discussed is USP7; the disease is B-cell chronic lymphocytic leukemia.