The benefit from ICI therapy in ER+/HER2− MP2 breast cancers was further demonstrated in the durvalumab and olaparib arm of the I-SPY2 trial, where the pCR rate improved from 22% with standard-of-care chemotherapy to 64% with the addition of durvalumab and olaparib [31]. The gene discussed is ESR1; the disease is breast carcinoma.