Innate and adaptive immune cells recruited to the tumor microenvironment by chemokines following noxious stimuli such as physical or chemical or infectious agents. Innate and adaptive immune cells release inflammatory mediators such as cytokines, chemokines, growth factors, proteolytic enzymes, activate transcription factors (NF-KB, STAT3,HIF-1a) results in tumor initiation, promotion, and progression. This article highlights about the role of innate and adaptive immune cells in tumor microenvironment.