Cancer is a major health problem worldwide and is one of the most prominent causes of morbidity and mortality in children and adults causing about 9 million deaths annually. The success of novel cancer therapies depends on the identification of functional targets that play an essential role in tumor growth and metastasis, survival and evasion from immunosurveillance. Costimulation through CD80 or through CD28-bearing T cells, regresses the growth in B cell lymphomas retard the proliferation and induce apoptosis. On the other hand Tuberculosis(MTB) a major infectious disease is becoming global emergency due to BCG failure and multidrug resistance and hence needs urgent attention from scientific community to develop alternative strategies to defeat the problems linked to the reemergence of TB. Macrophages activated through anti-B7-1 and anti-B7-2 mAbs showed enhanced microbicidal function and reduced the survival of MTB. Therefore this novel strategy can be effectively exploited to develop immunotherapy either using humanized antibodies against CD80 or CD86 or CD28 fusogenic proteins for the treatment of cancer especially relapse and refractory lymphomas and intracellular pathogens.