Table.2.

Examples of approved immune checkpoint inhibitors in cancer immune oncology.

Target	Ligand/ receptor	Inducer	Mechanism of invasion	Therapeutics-year of approval	Cancer	Ref
CTLA-4	CD80/CD86	T-cells activation signal	PKC-M recruits SHP-2 by interacting with the cytoplasmic tail; ectodomain competition with the counter receptor	Ipilimumab [Yervoy].-March 2011	Melanoma	Cheng et al., 2019, Velcheti et al., 2019, Sanaei et al., 2021. Vaddepally et al., 2020)
PD-1	PD-L1, PD-L2	T-cell receptor/ /B-cell receptor	The recruitment of SH2-domain protein tyrosine phosphatases to the ITSM cytoplasmic region of PD-1 suppresses the T-cell receptor's downstream signalling.	Pembrolizumab[keytruda].-September 2014	Bladder cancer	Cheng et al., 2019, Velcheti et al., 2019, Sanaei et al., 2021. Vaddepally et al., 2020)
		signalling		Nivolumab [Opdivo].-March 2015	kidney cancer
				Cemiplimab [Libtayo].-September 2018	Head and neck cancer
					Classical Hodgkin lymphoma
PD-L1, PD-L2	PD-1	FN-γ, cytokines, chemokine, STAT3 signaling	The recruitment of SH2-domain-containing protein tyrosine phosphatases to the ITSM cytoplasmic region of PD-1 inhibits downstream signalling.	Atezolizumab [Tecentriq].-May 2016	Bladder cancer	Cheng et al., 2019, Velcheti et al., 2019, Sanaei et al., 2021. Vaddepally et al., 2020)
				Avelumab [Bavencio].-November 2015	Merkel cell carcinoma
				Durvalumab [Imfinzi].-February 2016