CD8A and cancer: Therefore, in this review, we summarize the recent advances on CD8+ T cell-based cancer therapy, aiming to introduce the basics of CD8+ T cells through their generation, activation, function, and destination, together with new research findings, and to delineate the machinery regarding the immune escape of tumors by deceiving CD8+ T cells and immunotherapy regimens based on activation CD8+ T cells, all mingled with challenges and progresses.