Pathological response (PR) is an oncological outcome measure that indicates the therapeutic response to neoadjuvant therapy. In clinical trials involving neoadjuvant or perioperative interventions, overall survival and disease/event-free survival are typically the primary outcome measures. Although some evidence suggests that pathological complete response (pCR) can serve as a surrogate marker for the primary endpoint in prospective trials, it remains uncertain whether pCR is a true surrogate marker for patients with cancer undergoing curative resection across all solid tumours. Here, we review the role of PR as a surrogate marker and its associated methodological issues in the era of perioperative immune checkpoint inhibitors.