About PD-1
Programmed cell death protein 1 (PDCD1) is an immune-inhibitory receptor expressed in activated T cells; it is involved in the regulation of T-cell functions, including those of effector CD8+ T cells. In addition, this protein can also promote the differentiation of CD4+ T cells into T regulatory cells. PDCD1 is expressed in many types of tumors including melanomas, and has demonstrated to play a role in anti-tumor immunity. Moreover, this protein has been shown to be involved in safeguarding against autoimmunity, however, it can also contribute to the inhibition of effective anti-tumor and anti-microbial immunity. [provided by RefSeq, Aug 2020]

About Alexa Fluor 750
Alexa Fluor™ 750 (AF750, Alexa 750) has an excitation peak at 749 nm and an emission peak at 775 nm, and is spetrally similar to Cy®7 (GE Healthcare), APC-Fire™ 750 (BioLegend), CF®®750 (Biotium), DyLight™ 750 (ThermoFisher Scientific), iFluor® 750 (ATT Bioquest) and iFluor® 790 (ATT Bioquest). Alexa 750 is often used as a tandem fluorophore in flow cytometry or used on its own in fluorescence microscopy, in-vivo fluorescence microscopy or super-resolution microscopy applications.