PDCD1 and neoplasm: Although MRTX849/lapatinib led to significant regression in immune-competent tumor models, durable complete tumor regression responses were observed only by adding αPD-1 to the MRTX849/lapatinib combination therapy, suggesting that further enhancement of the antitumor immune response by blocking the PD-1 pathway may be critical for providing long-term disease control in patients.