In the current landscape of cancer research, much attention is focused on the tumor microenvironment (TME) at both the primary site and established metastases. However, the early micrometastatic niche remains poorly understood. Researchers from the Hospital del Mar Research Institute (HMRI) have pinpointed T cell immunoglobulin and mucin domain 3 (TIM3) as a key vulnerability in tumor micrometastasis, revealing a new target to halt metastatic progression at its origin.