Immune cells are distributed across various tissues. While a majority are concentrated in primary and secondary lymphoid organs such as the bone marrow, thymus, lymph nodes, and spleen, a subset resides in nonlymphoid organs, including the kidney, liver, and lung, as well as the peritoneal cavity, where they play critical roles in local immune surveillance and response. In this editorial, we outline concise and practical protocols for the isolation of immune cells from a range of lymphoid and nonlymphoid organs.