This is an international (5 countries) randomized phase III study with 2 cohorts, patients will be randomized 1:1 to endocrine therapy (cohort 1: exemestane 25 mg daily, cohort 2: fulvestrant 500mg days 1 and 15 cycle 1 and then day 1 every 4 weeks) plus palbociclib (125 mg daily x3 weeks every 4 weeks) vs. capecitabine (1,250 mg/m2 twice daily x2 weeks every 3 weeks). Postmenopausal patients with HR+/HER2 MBC are eligible if resistant to previous NSAI (letrozole or anastrozole) defined as: recurrence while on or within 12 months after the end of adjuvant treatment or progression while on or within 1 month after the end of treatment for MBC. Previous chemotherapy is permitted either in the (neo)adjuvant setting and/or as first line for MBC. Patients must have measurable disease according to RECIST 1.1 or bone lesions, lytic or mixed, in the absence of measurable disease.