GZMB and cancer: For cytotoxic T-cells that form GJ with cancer cells leading to an enhanced granzyme B activity in cancer cells it was thought that granzyme B or Ca2+ may be transferred (Hofmann et al., 2019) and macrophages that communicate via GJ with epithelial cells (Pepin et al., 2020) seem to mediate cGAMP via intercellular channels.